1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN"[
2 <!entity % dummy "IGNORE">
3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity contacting SYSTEM "contacting.sgml">
8 <!entity history SYSTEM "history.sgml">
9 <!entity copyright SYSTEM "copyright.sgml">
10 <!entity license SYSTEM "license.sgml">
11 <!entity p-version "3.0.29">
12 <!entity p-status "stable">
13 <!entity % p-not-stable "IGNORE">
14 <!entity % p-stable "INCLUDE">
15 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
16 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
17 <!entity % p-supp-userman "INCLUDE"> <!-- Include all from supported.sgml -->
18 <!entity my-copy "©"> <!-- kludge for docbook2man -->
19 <!entity % p-newstuff "INCLUDE"> <!-- exclude stuff from devel versions -->
20 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
21 <!entity my-app "<application>Privoxy</application>">
24 File : doc/source/faq.sgml
28 Copyright (C) 2001-2020 Privoxy Developers https://www.privoxy.org/
31 Based partially on the Internet Junkbuster FAQ originally written by and
32 Copyright (C) 1997 Anonymous Coders and Junkbusters Corporation.
33 http://www.junkbusters.com/
35 <Qandaset defaultlabel='qanda'>
50 ========================================================================
51 NOTE: Please read developer-manual/documentation.html before touching
54 Please we keep the info in this file as version independent as possible
55 so we only have to maintain one FAQ. Where significant changes are
56 made to Privoxy configuration, please note the change in such a way that
57 it makes sense to both users of older and newer versions.
58 ========================================================================
64 <article id="index" class="faq">
66 <title>Privoxy Frequently Asked Questions</title>
70 <!-- Completely the wrong markup, but very little is allowed -->
71 <!-- in this part of an article. FIXME -->
72 <link linkend="copyright">Copyright</link> &my-copy; 2001-2020 by
73 <ulink url="https://www.privoxy.org/">Privoxy Developers</ulink>
79 Note: this should generate a separate page, and a live link to it.
80 But it doesn't for some mysterious reason. Please leave commented
81 unless it can be fixed proper. For the time being, the copyright
82 statement will be in copyright.smgl.
86 <legalnotice id="legalnotice">
88 text goes here ........
98 <orgname>By: Privoxy Developers</orgname>
107 This is here to keep vim syntax file from breaking :/
108 If I knew enough to fix it, I would.
109 PLEASE DO NOT REMOVE! HB: hal@foobox.net
114 This FAQ gives quick answers to frequently asked questions about
115 <ulink url="https://www.privoxy.org/">Privoxy</ulink>.
116 It is not a substitute for the
117 <ulink url="../user-manual/index.html"><citetitle>Privoxy User Manual</citetitle></ulink>.
120 <!-- Include privoxy.sgml boilerplate: -->
121 <para>What is Privoxy?</para> &p-intro;
122 <!-- end boilerplate -->
125 Please note that this document is a work in progress. This copy represents
126 the state at the release of version &p-version;.
127 You can find the latest version of the document at <ulink
128 url="https://www.privoxy.org/faq/">https://www.privoxy.org/faq/</ulink>.
129 Please see the <link linkend="contact">Contact section</link> if you want to
130 contact the developers.
137 <!-- ~~~~~ New section ~~~~~ -->
139 <sect1 id="general"><title>General Information</title>
140 <sect2 renderas="sect3" id="who-uses"><title>Who should give &my-app; a try?</title>
142 Anyone who is interested in security, privacy, or in
143 finer-grained control over their web and Internet experience.
147 <sect2 renderas="sect3" id="bestchoice"><title>Is Privoxy the best choice for
150 &my-app; is certainly a good choice, especially for those who want more
151 control and security. Those with the willingness to read the documentation
152 and the ability to fine-tune their installation will benefit the most.
155 One of <application>Privoxy's</application>
156 strengths is that it is highly configurable giving you the ability to
157 completely personalize your installation. Being familiar with, or at least
158 having an interest in learning about <ulink
159 url="http://en.wikipedia.org/wiki/Http">HTTP</ulink> and other networking
160 protocols, <ulink url="http://en.wikipedia.org/wiki/Html">HTML</ulink>, and
161 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
162 Expressions</quote></ulink>
163 will be a big plus and will help you get the most out of &my-app;.
164 A new installation just includes a very basic configuration. The user
165 should take this as a starting point only, and enhance it as he or she
166 sees fit. In fact, the user is encouraged, and expected to, fine-tune the
170 Much of <application>Privoxy's</application> configuration can be done
171 with a <ulink url="http://en.wikipedia.org/wiki/Web_browser">Web browser</ulink>.
172 But there are areas where configuration is done using a
173 <ulink url="http://en.wikipedia.org/wiki/Text_editors">text editor</ulink>
174 to edit configuration files. Also note that the web-based action editor
175 doesn't use authentication and should only be enabled in environments
176 where all clients with access to &my-app; listening port can be trusted.
180 <sect2 renderas="sect3" id="proxymoron"><title>What is a <quote>proxy</quote>? How does
181 Privoxy work? </title>
183 A <ulink url="http://en.wikipedia.org/wiki/Proxy_server">web proxy</ulink>
184 is a service, based on a software such as &my-app;, that clients
185 (i.e. browsers) can use instead of connecting to web servers directly.
186 The clients then ask the proxy to request objects (web pages, images, movies etc)
187 on their behalf and to forward the data to the clients.
188 It is a <quote>go-between</quote>. For details, see
189 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">Wikipedia's proxy definition</ulink>.
192 There are many reasons to use web proxies, such as security (firewalling),
193 efficiency (caching) and others, and there are any number of proxies
194 to accommodate those needs.
197 &my-app; is a proxy that is primarily focused on
198 privacy enhancement, ad and junk elimination and freeing the user from
199 restrictions placed on his activities. Sitting between your browser(s) and the Internet,
200 it is in a perfect position to filter outbound personal information that your
201 browser is leaking, as well as inbound junk. It uses a variety of techniques to do
202 this, all of which are under your complete control via the various configuration
203 files and options. Being a proxy also makes it easier to share
204 configurations among multiple browsers and/or users.
208 <sect2 renderas="sect3" id="otherstuff">
209 <title>Does Privoxy do anything more than ad blocking?</title>
211 Yes, ad blocking is but one possible use. There are many, many ways &my-app;
212 can be used to sanitize and customize web browsing.
216 <sect2 renderas="sect3" id="newjb"><title>What is this new version of
217 <quote><citetitle>Junkbuster</citetitle></quote>?</title>
219 <!-- Include history.sgml -->
226 <sect2 renderas="sect3" id="whyprivoxy">
227 <title>Why <quote>Privoxy</quote>? Why change the name from
228 Junkbuster at all?</title>
230 Though outdated, Junkbusters Corporation continued to offer their original
231 version of the <application>Internet Junkbuster</application> for a while,
232 so publishing our <application> Junkbuster</application>-derived software
233 under the same name would have led to confusion.
236 There were also potential legal reasons not to use the
237 <application>Junkbuster</application> name, as it was (and maybe still is)
238 a registered trademark of Junkbusters Corporation.
239 There were, however, no objections from Junkbusters Corporation to the
240 <application>Privoxy</application> project itself, and they, in fact,
241 shared our ideals and goals.
244 The Privoxy developers also believed that there were so many improvements
245 over the original code, that it was time to make a clean break from the past
246 and make a name in their own right.
249 <application>Privoxy</application> is the
250 <quote><emphasis>Privacy Enhancing Proxy</emphasis></quote>. Also, its content
251 modification and junk suppression gives <emphasis>you</emphasis>, the user, more
252 control, more freedom, and allows you to browse your personal and
253 <quote><emphasis>private</emphasis> edition</quote> of the web.
257 <sect2 renderas="sect3" id="differs"><title>How does Privoxy differ
258 from the old Junkbuster?</title>
260 <application>Privoxy</application> picks up where
261 <application>Junkbuster</application> left off.
262 <application>Privoxy</application> still blocks ads and banners,
264 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>, and still
265 helps protect your privacy. But, most of these features have been enhanced,
266 and many new ones have been added, all in the same vein.
269 <application>Privoxy</application>'s new features include:
272 <!-- Include newfeatures.sgml: -->
278 <sect2 renderas="sect3" id="whatsanad">
279 <title>How does Privoxy know what is an ad, and what is not?</title>
281 <application>Privoxy</application>'s approach to blocking ads is twofold:
284 First, there are certain patterns in the <emphasis>locations</emphasis> (URLs)
285 of banner images. This applies to both the path (you wouldn't guess how many
286 web sites serve their banners from a directory called <quote>banners</quote>!)
287 and the host (blocking the big banner hosting services like doublecklick.net
288 already helps a lot). <application>Privoxy</application> takes advantage of this
289 fact by using <ulink url="../user-manual/actions-file.html#AF-PATTERNS">URL
290 patterns</ulink> to sort out and block the requests for things that sound
291 like they would be ads or banners.
294 Second, banners tend to come in certain <emphasis>sizes</emphasis>. But you
295 can't tell the size of an image by its URL without downloading it, and if you
296 do, it's too late to save bandwidth. Therefore, <application>Privoxy</application>
297 also inspects the HTML sources of web pages while they are loaded, and replaces
298 references to images with standard banner sizes by dummy references, so that
299 your browser doesn't request them anymore in the first place.
302 Both of this involves a certain amount of guesswork and is, of course, freely
303 and readily configurable.
307 <sect2 renderas="sect3" id="mistakes">
308 <title>Can Privoxy make mistakes?
309 This does not sound very scientific.</title>
311 Actually, it's a black art ;-) And yes, it is always possible to have a broad
312 rule accidentally block or change something by mistake. You will almost surely
313 run into such situations at some point. It is tricky writing rules to
314 cover every conceivable possibility, and not occasionally get false positives.
318 But this should not be a big concern since the
319 <application>Privoxy</application> configuration is very flexible, and
320 includes tools to help identify these types of situations so they can be
321 addressed as needed, allowing you to customize your installation.
322 (<link linkend="badsite">See the Troubleshooting section below</link>.)
327 <sect2 renderas="sect3" id="configornot">
328 <title>Will I have to configure Privoxy
329 before I can use it?</title>
331 That depends on your expectations.
332 The default installation should give you a good starting
333 point, and block <emphasis>most</emphasis> ads and unwanted content,
334 but many of the more advanced features are off by default, and require
335 you to activate them.
338 You do have to set up your browser to use
339 <application>Privoxy</application> (see the <link
340 linkend="firststep">Installation section below</link>).
343 And you will certainly run into situations where there are false positives,
344 or ads not being blocked that you may not want to see. In these cases, you
345 would certainly benefit by customizing <application>Privoxy's</application>
346 configuration to more closely match your individual situation. And we
347 encourage you to do this. This is where the real power of
348 <application>Privoxy</application> lies!
353 <sect2 renderas="sect3" id="lan">
354 <title>Can Privoxy run as a server on a network?</title>
356 Yes, &my-app; runs as a server already, and can easily be configured to
357 <quote>serve</quote> more than one client. See <link linkend="lanconfig">
358 How can I set up Privoxy to act as a proxy for my LAN</link> below.
362 <sect2 renderas="sect3" id="browsers2"><title>My browser does the same things as
363 Privoxy. Why should I use Privoxy at all?</title>
365 Modern browsers do indeed have <emphasis>some</emphasis> of the same
366 functionality as <application>Privoxy</application>. Maybe this is
367 adequate for you. But <application>Privoxy</application> is very
368 versatile and powerful, and can probably do a number of things
369 your browser just can't.
372 In addition, a proxy is good choice if you use multiple browsers, or
373 have a LAN with multiple computers since &my-app; can run as a server
374 application. This way all the configuration is in one place, and you don't
375 have to maintain a similar configuration for possibly many browsers or
379 Note, however, that it's recommended to leverage both your browser's
380 and <application>Privoxy's</application> privacy enhancing features
381 at the same time. While your browser probably lacks some features
382 &my-app; offers, it should also be able to do some things more
383 reliably, for example restricting and suppressing JavaScript.
387 <sect2 renderas="sect3" id="whytrust"><title>Why should I trust Privoxy?</title>
389 The most important reason is because you have access to
390 <emphasis>everything</emphasis>, and you can control everything. You can
391 check every line of every configuration file yourself. You can check every
392 last bit of source code should you desire. And even if you can't read code,
393 there should be some comfort in knowing that <!-- thousands of -->other people can,
394 and do read it. You can build the software from scratch, if you want,
395 so that you know the executable is clean, and that it is
396 <emphasis>yours</emphasis>. In fact, we encourage this level of scrutiny. It
397 is one reason we use &my-app; ourselves.
401 <sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a
402 warranty? Registration?</title>
404 <application>Privoxy</application> is free software and licensed under the <ulink
405 url="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GNU General Public License (GPL) version 2</ulink>.
406 It is free to use, copy, modify or distribute as you wish under the terms of this
407 license. Please see the <link linkend="copyright">Copyright</link> section for more
408 information on the license and copyright. Or the <filename>LICENSE</filename> file
409 that should be included.
412 There is <emphasis>no warranty</emphasis> of any kind, expressed, implied or otherwise.
413 That is something that would cost real money ;-) There is no registration either.
418 <sect2 renderas="sect3" id="spyware">
419 <title>Can Privoxy remove spyware? Adware? Viruses?</title>
421 No, at least not reliably enough to trust it. &my-app; is not designed to be
422 a malware removal tool and the default configuration doesn't even try to
423 filter out any malware.
426 &my-app; could help prevent contact from (known) sites that use such
427 tactics with appropriate configuration rules, and thus could conceivably
428 prevent contamination from such sites. However, keeping such a configuration
429 up to date would require a lot of time and effort that would be better spend
430 on keeping your software itself up to date so it doesn't have known
436 <sect2 renderas="sect3" id="otherads">
437 <title>Can I use Privoxy with other ad-blocking software?</title>
439 &my-app; should work fine with other proxies and other software in general.
442 But it is probably not necessary to use &my-app; in conjunction with other
443 ad-blocking products, and this could conceivably cause undesirable results.
444 It might be better to choose one software or the other and work a little to
445 tweak its configuration to your liking.
448 Note that this is an advice specific to ad blocking.
452 <sect2 renderas="sect3" id="help-the-developers"><title>I would like to help you, what can I do?</title>
454 <sect3 renderas="sect4" id="participate"><title>Would you like to participate?</title>
456 Well, we <emphasis>always</emphasis> need help. There is something for
457 everybody who wants to help us. We welcome new developers, packagers,
458 testers, documentation writers or really anyone with a desire to help in
459 any way. You <emphasis>DO NOT</emphasis> need to be a
460 <quote>programmer</quote>. There are many other tasks available. In fact,
461 the programmers often can't spend as much time programming because of some
462 of the other, more mundane things that need to be done, like checking the
463 Tracker feedback sections or responding to user questions on the mailing
467 So first thing, subscribe to the <ulink
468 url="https://lists.privoxy.org/mailman/listinfo/privoxy-users">Privoxy Users</ulink>
469 or the <ulink url="https://lists.privoxy.org/mailman/listinfo/privoxy-devel">Privoxy
470 Developers</ulink> mailing list, join the discussion, help out other users, provide general
471 feedback or report problems you noticed.
474 If you intend to help out with the trackers, you also might want to <ulink
475 url="https://sourceforge.net/user/registration">get an account on SourceForge.net</ulink>
476 so we don't confuse you with the other name-less users.
479 We also have a <ulink
480 url="../developer-manual/index.html">Developer's Manual</ulink>.
481 While it is partly out of date, it's still worth reading.
484 Our <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
485 may be of interest to you as well.
486 Please let us know if you want to work on one of the items listed.
490 <sect3 renderas="sect4" id="donate"><title>Would you like to donate?</title>
492 Donations are welcome. Our
493 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO list</ulink>
494 is rather long and being able to pay one (or more) developers to work on Privoxy
495 would make a huge difference, even if it was only for a couple of weeks. Donations may
496 also be used for Privoxy-related travel expenses (for example to attend conferences),
497 for hardware used for Privoxy development and for hosting expenses etc.
501 <application>Privoxy</application> is an associated
502 project of <ulink url="https://www.spi-inc.org/">Software
503 in the Public Interest (SPI)</ulink>, which allows us to receive
504 tax-deductible donations in the United States.
505 You can <ulink url="https://www.spi-inc.org/projects/privoxy/">donate via Paypal</ulink>
506 and <ulink url="https://co.clickandpledge.com/advanced/default.aspx?wid=34115">Click & Pledge</ulink>.
507 For details, please have a look at
508 <ulink url="https://www.spi-inc.org/donations">SPI's general donation page</ulink>.
512 If you have any questions regarding donations please mail to either the
513 public user mailing list or, if it's a private matter, to
514 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink> (Privoxy's SPI liaison)
519 <sect2 id="sponsor"><title>How can I become a sponsor and get my logo or link on privoxy.org?</title>
521 We are currently offering the following sponsor levels as an experiment:
525 <term>Gold (12000 USD/year)</term>
528 Logo or text link shown at the bottom of the
529 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
530 Logo, link and self description on the
531 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
536 <term>Silver (1200 USD/year)</term>
539 Logo or text link shown at the bottom of the
540 <ulink url="https://www.privoxy.org/">Privoxy homepage</ulink>.
541 Logo, link and self description on the
542 <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
547 <term>Bronze (600 USD/year)</term>
550 Logo and link on the <ulink url="https://www.privoxy.org/sponsors/">sponsor page</ulink>.
556 The logo sizes depend on the sponsor level. Logos are served from
557 our server, no requests are made to the sponsor website unless
558 the links are being used.
561 The details may change over time but changes will only affect new sponsors
562 (or existing sponsors that explicitly agreed to the changes).
565 If you want to become a sponsor, please contact
566 <ulink url="mailto:fk@fabiankeil.de">Fabian Keil</ulink>.
567 New sponsors are only accepted if no developer objects.
575 <!-- ~~~~~ New section ~~~~~ -->
577 <sect1 id="installation"><title>Installation</title>
579 <sect2 renderas="sect3" id="whichbrowsers">
580 <title>Which browsers are supported by Privoxy?</title>
582 Any browser that can be configured to use a proxy, which
583 should be virtually all browsers, including
584 <application>Firefox</application>, <application>Internet
585 Explorer</application>, <application>Opera</application>, and
586 <application>Safari</application> among others.
587 Direct browser support is not an absolute requirement since
588 <application>Privoxy</application> runs as a separate application and talks
589 to the browser in the standardized HTTP protocol, just like a web server
594 <sect2 renderas="sect3" id="whichos">
595 <title>Which operating systems are supported?</title>
597 Include supported.sgml here:
602 <sect2 renderas="sect3" id="email-client">
603 <title>Can I use Privoxy with my email client?</title>
605 As long as there is some way to set a HTTP proxy for the client, then yes,
606 any application can be used, whether it is strictly speaking a
607 <quote>browser</quote> or not. Though this may not be the best approach for
608 dealing with some of the common abuses of HTML in email. See <link
609 linkend="outlook">How can I configure <application>Privoxy</application>
610 with <application>Outlook</application>?</link> below for more on
614 Be aware that HTML email presents a number of unique security and privacy
615 related issues, that can require advanced skills to overcome. The developers
616 recommend using email clients that can be configured to convert HTML to plain
617 text for these reasons.
621 <!-- Nobody is going to still be doing this!
622 <sect2 renderas="sect3" id="newinstall"><title>Can I install
623 Privoxy over Junkbuster?</title>
625 We recommend you un-install <application>Junkbuster</application>
626 first to minimize conflicts and confusion. You may want to
627 save your old configuration files for future reference. The configuration
628 files and syntax have substantially changed, so you will need to manually
629 port your old patterns. See the <ulink url="../user-manual/upgradersnote.html">note
630 to upgraders</ulink> and <ulink url="../user-manual/installation.html">installation
631 chapter</ulink> in the <ulink url="../user-manual/index.html">User Manual</ulink>
635 Note: Some installers may automatically un-install
636 <application>Junkbuster</application>, if present!
642 <sect2 renderas="sect3" id="firststep">
643 <title>I just installed Privoxy. Is there anything
644 special I have to do now?</title>
647 All browsers should be told to use <application>Privoxy</application>
648 as a proxy by specifying the correct proxy address and port number
649 in the appropriate configuration area for the browser. It's possible
650 to combine &my-app; with a packet filter to intercept HTTP requests
651 even if the client isn't explicitly configured to use &my-app;,
652 but where possible, configuring the client is recommended. See
653 <ulink url="../user-manual/startup.html">the User Manual for more
654 details</ulink>. You should also flush your browser's memory and disk
655 cache to get rid of any cached junk items, and remove any stored
656 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>.
661 <sect2 renderas="sect3" id="localhost"><title>What is the proxy address of Privoxy?</title>
663 If you set up the <application>Privoxy</application> to run on
664 the computer you browse from (rather than your ISP's server or some
665 networked computer on a LAN), the proxy will be on <literal>127.0.0.1</literal>
666 (sometimes referred to as <quote>localhost</quote>,
667 which is the special name used by every computer on the Internet to refer
668 to itself) and the port will be 8118 (unless you used the <ulink
669 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
670 config option to tell <application>Privoxy</application> to run on
674 When configuring your browser's proxy settings you typically enter
675 the word <quote>localhost</quote> or the IP address <quote>127.0.0.1</quote>
676 in the boxes next to <quote>HTTP</quote> and <quote>Secure</quote> (HTTPS) and
677 then the number <quote>8118</quote> for <quote>port</quote>.
678 This tells your browser to send all web requests to <application>Privoxy</application>
679 instead of directly to the Internet.
682 <application>Privoxy</application> can also be used to proxy for
683 a Local Area Network. In this case, your would enter either the IP
684 address of the LAN host where <application>Privoxy</application>
685 is running, or the equivalent hostname, e.g. <literal>192.168.1.1</literal>.
686 Port assignment would be same as above. Note that
687 <application>Privoxy</application> doesn't listen on any LAN interfaces by
691 <application>Privoxy</application> does not currently handle
692 any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc.
696 <sect2 renderas="sect3" id="nothing">
697 <title>I just installed Privoxy, and nothing is happening.
698 All the ads are there. What's wrong?</title>
701 Did you configure your browser to use <application>Privoxy</application>
702 as a proxy? It does not sound like it. See above. You might also try flushing
703 the browser's caches to force a full re-reading of pages. You can verify
704 that <application>Privoxy</application> is running, and your browser
705 is correctly configured by entering the special URL:
706 <ulink url="http://p.p/">http://p.p/</ulink>.
707 <!-- Use http://p.p/ instead of http://config.privoxy.org/ here because
708 of potential redirect caching problem (see next Q). -->
709 This should take you to a page titled <quote>This is Privoxy..</quote> with
710 access to <application>Privoxy's</application> internal configuration.
711 If you see this, then you are good to go. If you receive a page saying
712 <quote>Privoxy is not running</quote>, then the browser is not set up to use
713 your <application>Privoxy</application> installation.
714 If you receive anything else (probably nothing at all), it could either
715 be that the browser is not set up correctly, or that
716 <application>Privoxy</application> is not running at all. Check the <ulink
717 url="../user-manual/config.html#LOGFILE">log file</ulink>. For instructions
718 on starting <application>Privoxy</application> and browser configuration,
719 see the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
720 on starting <application>Privoxy</application></ulink> in the
721 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
726 <sect2 renderas="sect3" id="notused">
727 <title>I get a <quote>Privoxy is not being used</quote> dummy page although
728 Privoxy is running and being used.</title>
731 First, make sure that Privoxy is <emphasis>really</emphasis> running and
732 being used by visiting <ulink url="http://p.p/">http://p.p/</ulink>. You
733 should see the <application>Privoxy</application> main page. If not, see
734 the <ulink url="https://www.privoxy.org/user-manual/startup.html">chapter
735 on starting <application>Privoxy</application></ulink> in the
736 <ulink url="https://www.privoxy.org/user-manual/">User Manual</ulink>.
740 Now if <ulink url="http://p.p/">http://p.p/</ulink> works for you, but
741 other parts of <application>Privoxy</application>'s web interface show
742 the dummy page, your browser has cached a redirection it encountered before
743 <application>Privoxy</application> was being used. You need to clear your
744 browser's cache. Note that shift-reloading the dummy page won't help, since
745 that'll only refresh the dummy page, not the redirection that lead you there.
749 The procedure for clearing the cache varies from browser to browser. For
750 example, <application>Mozilla/Netscape</application> users would click
751 <guibutton>Edit</guibutton> --> <guibutton>Preferences</guibutton> -->
752 <guibutton>Advanced</guibutton> --> <guibutton>Cache</guibutton> and
753 then click both <quote><guibutton>Clear Memory Cache</guibutton></quote>
754 and <quote><guibutton>Clear Disk Cache</guibutton></quote>.
755 In some <application>Firefox</application> versions it's
756 <guibutton>Tools</guibutton> --> <guibutton>Options</guibutton> -->
757 <guibutton>Privacy</guibutton> --> <guibutton>Cache</guibutton> and
758 then click <quote><guibutton>Clear Cache Now</guibutton></quote>.
759 <!-- In my Firefox versions it's the Netscape way. fk 2007-11-19-->
766 <!-- ~~~~~ New section ~~~~~ -->
768 <sect1 id="configuration"><title>Configuration</title>
769 <sect2 renderas="sect3" id="actionsfile">
770 <title>What exactly is an <quote>actions</quote> file?</title>
773 &my-app; utilizes the concept of <quote>
774 <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink></quote>
775 that are used to manipulate and control web page data.
776 <ulink url="../user-manual/actions-file.html">Actions files</ulink>
777 are where these <ulink url="../user-manual/actions-file.html#ACTIONS">actions</ulink>
778 that <application>Privoxy</application> could take while processing a certain
779 request, are configured. Typically, you would define a set of default actions
780 that apply globally to all URLs, then add exceptions to these defaults where needed.
781 There is a wide array of actions available that give the user a high degree
782 of control and flexibility on how to process each and every web page.
786 Actions can be defined on a <ulink
787 url="../user-manual/actions-file.html#AF-PATTERNS">URL pattern</ulink> basis, i.e.
788 for single URLs, whole web sites, groups or parts thereof etc. Actions can also be
789 grouped together and then applied to requests matching one or more patterns.
790 There are many possible actions that might apply to any given site. As an example,
791 if you are blocking <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
792 as one of your default actions, but need to accept cookies from a given site,
793 you would need to define an exception for this site in one of your actions
794 files, preferably in <filename>user.action</filename>.
799 <sect2 renderas="sect3" id="actionss">
800 <title>The <quote>actions</quote> concept confuses me. Please list
801 some of these <quote>actions</quote>.</title>
803 For a comprehensive discussion of the actions concept, please refer
804 to the <ulink url="../user-manual/actions-file.html">actions file
805 chapter</ulink> in the <ulink url="../user-manual/index.html">User
806 Manual</ulink>. It includes a <ulink
807 url="../user-manual/actions-file.html#ACTIONS">list of all actions</ulink>
808 and an <ulink url="../user-manual/actions-file.html#ACT-EXAMPLES">actions
809 file tutorial</ulink> to get you started.
814 <sect2 renderas="sect3" id="actconfig">
815 <title>How are actions files configured? What is the easiest
816 way to do this?</title>
819 Actions files are just text files in a special syntax and can be edited
820 with a text editor. But probably the easiest way is to access
821 <application>Privoxy</application>'s user interface with your web browser
822 at <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
823 (Shortcut: <ulink url="http://p.p/">http://p.p/</ulink>) and then select
824 <quote><ulink url="http://config.privoxy.org/show-status">View &
825 change the current configuration</ulink></quote> from the menu. Note
826 that this feature must be explicitly enabled in the main config file
828 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
833 <sect2 renderas="sect3">
834 <title>There are several different <quote>actions</quote> files. What are
835 the differences?</title>
837 Please have a look at the <ulink url="../user-manual/actions-file.html">the actions chapter</ulink>
838 in the <ulink url="../user-manual/index.html">User Manual</ulink> for a detailed explanation.
843 <sect2 renderas="sect3" id="getupdates"><title>Where can I get updated Actions Files?</title>
845 Based on your feedback and the continuing development, updates of
846 <filename>default.action</filename> are available from
848 url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=default.action.master;hb=HEAD">git</ulink>.
852 If you wish to receive an email notification whenever we release updates of
853 <application>Privoxy</application> or the actions file, <ulink
854 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
855 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
860 <sect2 renderas="sect3" id="newconfig"><title>Can I use my old config files?</title>
862 The syntax and purpose of configuration files has remained roughly the
863 same throughout the 3.x series, but backwards compatibility is not guaranteed.
864 Also each release contains updated, <quote>improved</quote> versions and it is
865 therefore strongly recommended to install the newer configuration files
866 and merge back your modifications.
870 <sect2 renderas="sect3" id="difficult">
871 <title>Why is the configuration so complicated?</title>
873 <quote>Complicated</quote> is in the eye of the beholder.
876 Privoxy is currently mainly written by and for people who are already
877 familiar with the underlying concepts like regular expressions, HTTP and HTML,
878 or are willing to become familiar with them to be able to get the most
879 out of a powerful and flexible tool such as Privoxy.
882 While everybody is expected to be able to get a Privoxy default installation
883 up and running, fine-tuning requires a certain amount of background
884 information and Privoxy's documentation mainly concentrates on the
885 Privoxy-specific parts while only providing references to the rest.
888 If you or anyone you know has the skills, time and energy to
889 reduce the barrier of entry, please <link linkend="participate">get involved</link>.
893 <sect2 renderas="sect3" id="yahoo"><title>How can I make my Yahoo/Hotmail/Gmail account work?</title>
895 The default configuration shouldn't impact the usability of any of these services.
896 It may, however, make all <ulink
897 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>
898 temporary, so that your browser will forget your
899 login credentials in between browser sessions. If you would like not to have to log
900 in manually each time you access those websites, simply turn off all cookie handling
901 for them in the <filename>user.action</filename> file. An example for yahoo might
904 <screen># Allow all cookies for Yahoo login:
906 { -<ulink url="../user-manual/actions-file.html#CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</ulink> -<ulink url="../user-manual/actions-file.html#CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</ulink> -<ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink> }
907 .login.yahoo.com</screen>
909 These kinds of sites are often quite complex and heavy with
910 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> and
911 thus <quote>fragile</quote>. So if <emphasis>still</emphasis> a problem,
913 url="../user-manual/actions-file.html#ALIASES">alias</ulink> just for such
916 <screen># Gmail is a _fragile_ site:
918 { <literal>fragile</literal> }
920 mail.google.com</screen>
922 Be sure to flush your browser's caches whenever making these kinds of
923 changes, just to make sure the changes <quote>take</quote>.
926 Make sure the domain, host and path are appropriate as well. Your browser can
927 tell you where you are specifically and you should use that information for
928 your configuration settings. Note that above it is not referenced as
929 <literal>gmail.com</literal>, which is a valid domain name.
934 <sect2 renderas="sect3" id="configfiles"> <title>What's the difference between the
935 <quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advanced</quote> defaults?</title>
937 Configuring <application>Privoxy</application> is not entirely trivial. To
938 help you get started, we provide you with three different default action
939 <quote>profiles</quote> in the web based actions file editor at <ulink
940 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
941 See the <ulink url="../user-manual/actions-file.html"><citetitle>User
942 Manual</citetitle></ulink> for a list of actions, and how the default
947 Where the defaults are likely to break some sites, exceptions for
948 known popular <quote>problem</quote> sites are included, but in
949 general, the more aggressive your default settings are, the more exceptions
950 you will have to make later. New users are best to start off in
951 <quote>Cautious</quote> setting. This is safest and will have the fewest
952 problems. See the <ulink
953 url="../user-manual/index.html"><citetitle>User Manual</citetitle></ulink>
954 for a more detailed discussion.
958 It should be noted that the <quote>Advanced</quote> profile (formerly known
959 as the <quote>Adventuresome</quote> profile) is more
960 aggressive, and will make use of some of
961 <application>Privoxy's</application> advanced features. Use at your own risk!
966 <sect2 renderas="sect3" id="browseconfig"> <title>Why can I change the configuration
967 with a browser? Does that not raise security issues?</title>
969 It may seem strange that regular users can edit the config files with their
970 browsers, although the whole <filename>/etc/privoxy</filename> hierarchy
971 belongs to the user <quote>privoxy</quote>, with only 644 permissions.
974 When you use the browser-based editor, <application>Privoxy</application>
975 itself is writing to the config files. Because
976 <application>Privoxy</application> is running as the user <quote>privoxy</quote>,
977 it can update its own config files.
980 If you run <application>Privoxy</application> for multiple untrusted users (e.g. in
981 a LAN) or aren't entirely in control of your own browser, you will probably want
982 to make sure that the web-based editor and remote toggle features are
983 <quote>off</quote> by setting <quote><literal><ulink
984 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>
985 0</literal></quote> and <quote><literal><ulink
986 url="../user-manual/config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</ulink>
987 0</literal></quote> in the <ulink url="../user-manual/config.html">main configuration file</ulink>.
990 As of &my-app; 3.0.7 these options are disabled by default.
995 <sect2 renderas="sect3" id="filterfile">
996 <title>What is the <filename>default.filter</filename> file? What is a <quote>filter</quote>?</title>
998 The <ulink url="../user-manual/filter-file.html"><filename>default.filter</filename></ulink>
999 file is where <emphasis>filters</emphasis> as supplied by the developers are defined.
1000 Filters are a special subset of actions that can be used to modify or
1001 remove web page content or headers on the fly. Content filters can
1002 be applied to <emphasis>anything</emphasis> in the page source,
1003 header filters can be applied to either server or client headers.
1004 Regular expressions are used to accomplish this.
1007 There are a number of pre-defined filters to deal with common annoyances. The
1008 filters are only defined here, to invoke them, you need to use the
1010 url="../user-manual/actions-file.html#FILTER"><literal>filter</literal>
1011 action</ulink> in one of the actions files. Content filtering is automatically
1012 disabled for inappropriate MIME types, but if you know better than Privoxy
1013 what should or should not be filtered you can filter any content you like.
1017 <emphasis>not</emphasis> be confused with <ulink
1018 url="../user-manual/actions-file.html#BLOCK"><literal>blocks</literal></ulink>, which
1019 is a completely different action, and is more typically used to block ads and
1024 If you are familiar with regular expressions, and HTML, you can look at
1025 the provided <filename>default.filter</filename> with a text editor and define
1026 your own filters. This is potentially a very powerful feature, but
1027 requires some expertise in both regular expressions and HTML/HTTP.
1028 <![%p-newstuff;[ You should
1029 place any modifications to the default filters, or any new ones you create
1030 in a separate file, such as <filename>user.filter</filename>, so they won't
1031 be overwritten during upgrades.
1032 The ability to define multiple filter files
1033 in <filename>config</filename> is a new feature as of v. 3.0.5.]]>
1037 There is no GUI editor option for this part of the configuration,
1038 but you can disable/enable the various pre-defined filters of the included
1039 <filename>default.filter</filename> file with the <ulink
1040 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1041 Note that the custom actions editor must be explicitly enabled in
1042 the main config file (see <ulink
1043 url="../user-manual/config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</ulink>).
1047 If you intend to develop your own filters, you might want to have a look at
1049 url="https://www.fabiankeil.de/sourcecode/pft/">Privoxy-Filter-Test</ulink>.
1054 <sect2 renderas="sect3" id="lanconfig">
1055 <title>How can I set up Privoxy to act as a proxy for my
1058 By default, <application>Privoxy</application> only responds to requests
1059 from <literal>127.0.0.1</literal> (localhost). To have it act as a server for
1060 a network, this needs to be changed in the <ulink
1061 url="../user-manual/config.html">main configuration file</ulink>. Look for
1063 url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink></literal>
1064 option, which may be commented out with a <quote>#</quote> symbol. Make sure
1065 it is uncommented, and assign it the address of the LAN gateway interface,
1066 and port number to use. Assuming your LAN address is 192.168.1.1 and you
1067 wish to run <application>Privoxy</application> on port 8118, this line
1072 listen-address 192.168.1.1:8118</screen>
1075 Save the file, and restart <application>Privoxy</application>. Configure
1076 all browsers on the network then to use this address and port number.
1080 Alternately, you can have <application>Privoxy</application> listen on
1081 all available interfaces:
1085 listen-address :8118</screen>
1088 And then use <application>Privoxy's</application>
1090 url="../user-manual/config.html#PERMIT-ACCESS">permit-access</ulink>
1091 feature to limit connections. A firewall in this situation is recommended
1096 The above steps should be the same for any TCP network, regardless of
1101 If you run <application>Privoxy</application> on a LAN with untrusted users,
1102 we recommend that you double-check the <ulink
1103 url="../user-manual/config.html#ACCESS-CONTROL">access control and security</ulink>
1110 <sect2 renderas="sect3" id="noseeum">
1111 <title>Instead of ads, now I get a checkerboard pattern. I don't want to see anything.</title>
1113 The replacement for blocked images can be controlled with the <ulink
1114 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1115 action</ulink>. You have the choice of a checkerboard pattern, a transparent 1x1 GIF
1116 image (aka <quote>blank</quote>), or a redirect to a custom image of your choice.
1117 Note that this choice only has effect for images which are blocked as images, i.e.
1118 whose URLs match both a <literal><ulink
1119 url="../user-manual/actions-file.html#HANDLE-AS-IMAGE">handle-as-image</ulink></literal>
1120 <emphasis>and</emphasis> <literal><ulink
1121 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> action.
1124 If you want to see nothing, then change the <ulink
1125 url="../user-manual/actions-file.html#SET-IMAGE-BLOCKER"><literal>set-image-blocker</literal>
1126 action</ulink> to <quote>blank</quote>. This can be done by editing the
1127 <filename>user.action</filename> file, or through the <ulink
1128 url="http://config.privoxy.org/show-status">web-based actions file editor</ulink>.
1133 <sect2 renderas="sect3" id="whyseeum">
1134 <title>Why would anybody want to see a checkerboard pattern?</title>
1136 Remember that <link linkend="whatsanad">telling which image is an ad and which
1137 isn't</link>, is an educated guess. While we hope that the standard configuration
1138 is rather smart, it will make occasional mistakes. The checkerboard image is visually
1139 decent, and it shows you where images have been blocked, which can be very
1140 helpful in case some navigation aid or otherwise innocent image was
1141 erroneously blocked. It is recommended for new users so they can
1142 <quote>see</quote> what is happening. Some people might also enjoy seeing how
1143 many banners they <emphasis>don't</emphasis> have to see.
1148 <sect2 renderas="sect3" id="blockedbytext">
1149 <title>I see some images being replaced with text
1150 instead of the checkerboard image. Why and how do I get rid of this?</title>
1152 This happens when the banners are not embedded in the HTML code of the
1153 page itself, but in separate HTML (sub)documents that are loaded into (i)frames
1154 or (i)layers, and these external HTML documents are blocked. Being non-images
1155 they get replaced by a substitute HTML page rather than a substitute image,
1156 which wouldn't work out technically, since the browser expects and accepts
1157 only HTML when it has requested an HTML document.
1160 The substitute page adapts to the available space and shows itself as a
1161 miniature two-liner if loaded into small frames, or full-blown with a
1162 large red "BLOCKED" banner if space allows.
1165 If you prefer the banners to be blocked by images, you must see to it that
1166 the HTML documents in which they are embedded are not blocked. Clicking
1167 the <quote>See why</quote> link offered in the substitute page will show
1168 you which rule blocked the page. After changing the rule and un-blocking
1169 the HTML documents, the browser will try to load the actual banner images
1170 and the usual image blocking will (hopefully!) kick in.
1175 <sect2 renderas="sect3" id="srvany">
1176 <title>Can Privoxy run as a service
1177 on Win2K/NT/XP?</title>
1179 Yes. Full <application>Windows</application> service
1180 functionality was introduced in <application>Privoxy</application> 3.0.5.
1181 See <ulink url="../user-manual/installation.html#INSTALLATION-PACK-WIN">
1182 the <citetitle>User Manual</citetitle></ulink> for details on how to install and configure
1183 <application>Privoxy</application> as a service.
1188 <sect2 renderas="sect3" id="otherproxy">
1189 <title>How can I make Privoxy work with other proxies?</title>
1191 This can be done and is often useful to combine the benefits of
1192 <application>Privoxy</application> with those of a another proxy,
1193 for example to cache content.
1195 url="../user-manual/config.html#FORWARDING">forwarding chapter</ulink>
1196 in the <ulink url="../user-manual/index.html">User Manual</ulink> which
1197 describes how to do this. If you intend to use Privoxy with Tor,
1198 please also have a look at
1199 <link linkend="TOR">How do I use Privoxy together with Tor</link>.
1203 <sect2 renderas="sect3" id="port-80">
1204 <title>Can I just set Privoxy to use port 80
1205 and thus avoid individual browser configuration?</title>
1208 No, its more complicated than that. This only works with special kinds
1209 of proxies known as <quote>intercepting</quote> proxies
1210 (<link linkend="INTERCEPTING">see below</link>).
1215 <sect2 renderas="sect3" id="transparent">
1216 <title>Can Privoxy run as a <quote>transparent
1217 </quote> proxy?</title>
1219 The whole idea of Privoxy is to modify client requests
1220 and server responses in all sorts of ways and therefore
1221 it's not a transparent proxy as described in
1222 <ulink url="http://tools.ietf.org/html/rfc2616">RFC 2616</ulink>.
1225 However, some people say <quote>transparent proxy</quote> when they
1226 mean <quote>intercepting proxy</quote>. If you are one of them,
1227 please read the <link linkend="INTERCEPTING">next entry</link>.
1232 <sect2 renderas="sect3" id="intercepting">
1233 <title>Can Privoxy run as a <quote>intercepting</quote> proxy?</title>
1235 <application>Privoxy</application> can't intercept traffic itself,
1236 but it can handle requests that where intercepted and redirected
1237 with a packet filter (like <application>PF</application> or
1238 <application>iptables</application>), as long as the <literal>Host</literal>
1242 As the <literal>Host</literal> header is required by HTTP/1.1 and as most
1243 web sites rely on it anyway, this limitation shouldn't be a problem.
1246 Please refer to your packet filter's documentation to learn how to
1247 intercept and redirect traffic into <application>Privoxy</application>.
1248 Afterward you just have to configure <application>Privoxy</application> to
1249 <ulink url="../user-manual/config.html#ACCEPT-INTERCEPTED-REQUESTS">accept
1250 intercepted requests</ulink>.
1255 <sect2 renderas="sect3" id="outlook">
1256 <title>How can I configure Privoxy for use with Outlook?</title>
1258 Versions of <application>Outlook</application> prior to Office 2007, use
1259 <application>Internet Explorer</application> components to both render HTML,
1260 and fetch any HTTP requests that may be embedded in an HTML email. So however
1261 you have <application>Privoxy</application> configured to work with IE, this
1262 configuration should automatically be shared, at least with older version of
1266 Starting with Office 2007, Microsoft is instead using the MS-Word rendering
1267 engine with Outlook. It is unknown whether this can be configured to use a
1269 <!-- FIXME HB 2009-02-15 -->
1273 <sect2 renderas="sect3" id="outlook-more">
1274 <title>How can I have separate rules just for HTML mail?</title>
1276 The short answer is, you can't. <application>Privoxy</application> has no way
1277 of knowing which particular application makes a request, so there is no way to
1278 distinguish between web pages and HTML mail.
1279 <application>Privoxy</application> just blindly proxies all requests. In the
1280 case of <application>Outlook Express</application> (see above), OE uses
1281 IE anyway, and there is no way for <application>Privoxy</application> to ever
1282 be able to distinguish between them (nor could any other proxy type application for
1286 For a good discussion of some of the issues involved (including privacy and
1287 security issues), see
1288 <ulink url="https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118">https://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118</ulink>.
1292 <sect2 renderas="sect3" id="sneaky-cookies">
1293 <title>I sometimes notice cookies sneaking through. How?</title>
1296 url="http://en.wikipedia.org/wiki/Browser_cookie">Cookies</ulink> can be
1297 set in several ways. The classic method is via the
1298 <literal>Set-Cookie</literal> HTTP header. This is straightforward, and an
1299 easy one to manipulate, such as the &my-app; concept of
1300 <ulink url="../user-manual/actions-file.html#SESSION-COOKIES-ONLY">session-cookies-only</ulink>.
1301 There is also the possibility of using
1302 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink> to
1303 set cookies (&my-app; calls these <literal>content-cookies</literal>). This
1304 is trickier because the syntax can vary widely, and thus requires a certain
1305 amount of guesswork. It is not realistic to catch all of these short of
1306 disabling Javascript, which would break many sites. And lastly, if the
1307 cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond
1308 <application>Privoxy's</application> reach unless you enable
1309 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>.
1312 All in all, &my-app; can help manage cookies in general, can help minimize
1313 the loss of privacy posed by cookies, but can't realistically stop all
1318 <sect2 renderas="sect3" id="evil-cookies">
1319 <title>Are all cookies bad? Why?</title>
1321 No, in fact there are many beneficial uses of
1323 url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>. Cookies are just a
1324 method that browsers can use to store data between pages, or between browser
1325 sessions. Sometimes there is a good reason for this, and the user's life is a
1326 bit easier as a result. But there is a long history of some websites taking
1327 advantage of this layer of trust, and using the data they glean from you and
1328 your browsing habits for their own purposes, and maybe to your potential
1329 detriment. Such sites are using you and storing their data on your system.
1330 That is why the privacy conscious watch from whom those cookies come, and why
1331 they really <emphasis>need</emphasis> to be there.
1335 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">Wikipedia cookie
1336 definition</ulink> for more.
1340 <sect2 renderas="sect3" id="allow-cookies">
1341 <title>How can I allow permanent cookies for my trusted sites?</title>
1344 There are several actions that relate to cookies. The default behavior is to
1345 allow only <quote>session cookies</quote>, which means the cookies only last
1346 for the current browser session. This eliminates most kinds of abuse related
1347 to cookies. But there may be cases where you want cookies to last.
1350 To disable all cookie actions, so that cookies are allowed unrestricted,
1351 both in and out, for <literal>example.com</literal>:
1354 { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} }
1355 .example.com</screen>
1357 Place the above in <filename>user.action</filename>. Note that some of these may
1358 be off by default anyway, so this might be redundant, but there is no harm
1359 being explicit in what you want to happen. <filename>user.action</filename>
1360 includes an alias for this situation, called
1361 <literal>allow-all-cookies</literal>.
1365 <sect2 renderas="sect3" id="multiples">
1366 <title>Can I have separate configurations for different users?</title>
1368 Each instance of <application>Privoxy</application> has its own
1369 configuration, including such attributes as the TCP port that it listens on.
1370 What you can do is run multiple instances of <application>Privoxy</application>, each with
1372 <ulink url="../user-manual/config.html#LISTEN-ADDRESS">listen-address</ulink>
1373 configuration setting, and configuration path, and then
1374 each of these can have their own configurations. Think of it as per-port
1378 Simple enough for a few users, but for large installations, consider having
1379 groups of users that might share like configurations.
1383 <sect2 renderas="sect3" id="whitelists">
1384 <title>Can I set-up Privoxy as a whitelist of
1385 <quote>good</quote> sites?</title>
1387 Sure. There are a couple of things you can do for simple white-listing.
1388 Here's one real easy one:
1391 ############################################################
1393 ############################################################
1394 { <ulink url="../user-manual/actions-file.html#BLOCK">+block</ulink> }
1395 / # Block *all* URLs
1397 ############################################################
1399 ############################################################
1400 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1403 games.example.com</screen>
1405 This allows access to only those three sites by first blocking all URLs, and
1406 then subsequently allowing three specific exceptions.
1409 Another approach is <application>Privoxy's</application>
1410 <literal>trustfile</literal> concept, which incorporates the notion of
1411 <quote>trusted referrers</quote>. See the <ulink
1412 url="../user-manual/config.html#TRUSTFILE">Trust documentation</ulink>
1416 These are fairly simple approaches and are not completely foolproof. There
1417 are various other configuration options that should be disabled (described
1418 elsewhere here and in <ulink url="../user-manual/">the User Manual</ulink>)
1419 so that users can't modify their own configuration and easily circumvent the
1424 <sect2 renderas="sect3" id="no-adblock">
1425 <title>How can I turn off ad-blocking?</title>
1427 Ad blocking is achieved through a complex application of various &my-app;
1428 <ulink url="../user-manual/actions-file.html">actions</ulink>. These
1429 actions are deployed against simple images, banners, flash animations,
1430 text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as
1431 just turning one or two actions off. The various actions that make up
1432 &my-app; ad blocking are hard-coded into the default configuration files. It
1433 has been assumed that everyone using &my-app; is interested in this
1437 If you want to do without this, there are several approaches you can take:
1438 You can manually undo the many block rules in
1439 <filename>default.action</filename>. Or even easier, just create your own
1440 <filename>default.action</filename> file from scratch without the many ad
1441 blocking rules, and corresponding exceptions. Or lastly, if you are not
1442 concerned about the additional blocks that are done for privacy reasons, you
1443 can very easily over-ride <emphasis>all</emphasis> blocking with the
1444 following very simple rule in your <filename>user.action</filename>:
1447 # Unblock everybody, everywhere
1448 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> }
1449 / # UN-Block *all* URLs</screen>
1451 Or even a more comprehensive reversing of various ad related actions:
1454 # Unblock everybody, everywhere, and turn off appropriate filtering, etc
1455 { <ulink url="../user-manual/actions-file.html#BLOCK">-block</ulink> \
1456 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-SIZE">-filter{banners-by-size}</ulink> \
1457 <ulink url="../user-manual/actions-file.html#FILTER-BANNERS-BY-LINK">-filter{banners-by-link}</ulink> \
1458 <literal>allow-popups</literal> \
1460 / # UN-Block *all* URLs and allow ads</screen>
1462 This last <quote>action</quote> in this compound statement,
1463 <literal>allow-popups</literal>, is an <ulink
1464 url="../user-manual/actions-file.html#ALIASES">alias</ulink> that disables
1465 various pop-up blocking features.
1469 <sect2 renderas="sect3" id="templates">
1470 <title>How can I have custom template pages, like the
1471 <emphasis>BLOCKED</emphasis> page?</title>
1473 &my-app; <quote>templates</quote> are specialized text files utilized by
1474 &my-app; for various purposes and can easily be modified using any text
1475 editor. All the template pages are installed in a sub-directory appropriately
1476 named: <filename>templates</filename>. Knowing something about HTML syntax
1477 will of course be helpful.
1480 Be forewarned that the default templates are subject to being overwritten
1481 during upgrades. You can, however, create completely new templates,
1482 place them in another directory and specify the alternate path in the main
1483 <filename>config</filename>. For details, have a look at the <ulink
1484 url="../user-manual/config.html#TEMPLDIR">templdir</ulink> option.
1488 <sect2 renderas="sect3" id="blockall">
1489 <title>How can I remove the <quote>Go There Anyway</quote> link from
1490 the <emphasis>BLOCKED</emphasis> page?</title>
1492 There is more than one way to do it (although Perl is not involved).
1495 Editing the BLOCKED template page (see above) may dissuade some users, but
1496 this method is easily circumvented. Where you need this level of control, you
1497 might want to build &my-app; from source, and disable various features that are
1498 available as compile-time options. You should
1499 <command>configure</command> the sources as follows:
1502 ./configure --disable-toggle --disable-editor --disable-force</screen>
1504 This will create an executable with hard-coded security features so that
1505 &my-app; does not allow easy bypassing of blocked sites, or changing the
1506 current configuration via any connected user's web browser.
1509 Finally, all of these features can also be toggled on/off via options in
1510 <application>Privoxy's</application> main <ulink
1511 url="../user-manual/config.html#ACCESS-CONTROL">config</ulink> file which
1512 means you don't have to recompile anything.
1518 <!-- ~ End section ~ -->
1521 <!-- ~~~~~ New section ~~~~~ -->
1523 <sect1 id="misc"><title>Miscellaneous</title>
1525 <sect2 renderas="sect3" id="slowsme">
1526 <title>How much does Privoxy slow my browsing down? This
1527 has to add extra time to browsing.</title>
1529 How much of an impact depends on many things, including the CPU of the host
1530 system, how aggressive the configuration is, which specific actions are being triggered,
1531 the size of the page, the bandwidth of the connection, etc.
1534 Overall, it should not slow you down any in real terms, and may actually help
1535 speed things up since ads, banners and other junk are not typically being
1536 retrieved and displayed. The actual processing time required by
1537 <application>Privoxy</application> itself for each page, is relatively small
1538 in the overall scheme of things, and happens very quickly. This is typically
1539 more than offset by time saved not downloading and rendering ad images and
1540 other junk content (if ad blocking is being used).
1544 <quote>Filtering</quote> content via the <literal><ulink
1545 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> or
1547 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1548 actions may cause a perceived slowdown, since the entire document
1549 needs to be buffered before displaying. And on very large documents,
1550 filtering may have some measurable impact. How much depends on the page size,
1551 the actual definition of the filter(s), etc. See below. Most other actions
1552 have little to no impact on speed.
1555 Also, when filtering is enabled but zlib support isn't available, compression
1556 is often disabled (see <ulink
1557 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>).
1558 This can have an impact on speed as well, although it's probably smaller than
1559 you might think. Again, the page size, etc. will determine how much of an impact.
1565 <sect2 renderas="sect3" id="loadingtimes"><title>I notice considerable
1566 delays in page requests. What's wrong?</title>
1568 If you use any <literal><ulink
1569 url="../user-manual/actions-file.html#FILTER">filter</ulink></literal> action,
1570 such as filtering banners by size, web-bugs etc, or the <literal><ulink
1571 url="../user-manual/actions-file.html#DEANIMATE-GIFS">deanimate-gifs</ulink></literal>
1572 action, the entire document must be loaded into memory in order for the filtering
1573 mechanism to work, and nothing is sent to the browser during this time.
1576 The loading time typically does not really change much in real numbers, but
1577 the feeling is different, because most browsers are able to start rendering
1578 incomplete content, giving the user a feeling of "it works". This effect is
1579 more noticeable on slower dialup connections. Extremely large documents
1580 may have some impact on the time to load the page where there is filtering
1581 being done. But overall, the difference should be very minimal. If there is a
1582 big impact, then probably some other situation is contributing (like
1583 anti-virus software).
1586 Filtering is automatically disabled for inappropriate MIME types. But note
1587 that if the web server mis-reports the MIME type, then content that should
1588 not be filtered, could be. <application>Privoxy</application> only knows how
1589 to differentiate filterable content because of the MIME type as reported by
1590 the server, or because of some configuration setting that enables/disables
1595 <sect2 renderas="sect3" id="configurl"><title>What are "http://config.privoxy.org/" and
1596 "http://p.p/"?</title>
1598 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink> is the
1599 address of <application>Privoxy</application>'s built-in user interface, and
1600 <ulink url="http://p.p/">http://p.p/</ulink> is a shortcut for it.
1603 Since <application>Privoxy</application> sits between your web browser and the Internet,
1604 it can simply intercept requests for these addresses and answer them with its built-in
1605 <quote>web server</quote>.
1608 This also makes for a good test for your browser configuration: If entering the
1609 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1610 takes you to a page saying <quote>This is Privoxy ...</quote>, everything is OK.
1611 If you get a page saying <quote>Privoxy is not working</quote> instead, then
1612 your browser didn't use <application>Privoxy</application> for the request,
1613 hence it could not be intercepted, and you have accessed the <emphasis>real</emphasis>
1614 web site at config.privoxy.org.
1617 Note that config.privoxy.org resolves to a public IP address.
1618 If you use config.privoxy.org as ping or traceroute target you will
1619 reach the system on the Internet (Privoxy can't intercept ICMP requests).
1620 If you want to ping the system Privoxy runs on,
1621 you should use its IP address or local DNS name (if it has got one).
1627 out of date 09/02/06 HB
1628 <sect2 renderas="sect3" id="blocklist"><title>Do you still maintain the blocklists?</title>
1630 No. The patterns for blocking now reside (among other things) in the <ulink
1631 url="../user-manual/actions-file.html">actions files</ulink>, which are
1632 actively maintained instead. See next question ...
1636 <sect2 renderas="sect3" id="newads"><title>How can I submit new ads, or report
1639 Please see the <link linkend="contact">Contact section</link> for
1640 various ways to interact with the developers.
1645 <sect2 renderas="sect3" id="newads2"><title>If I do submit missed ads, will
1646 they be included in future updates?</title>
1648 Whether such submissions are eventually included in the
1649 <filename>default.action</filename> configuration file depends on how
1650 significant the issue is. We of course want to address any potential
1651 problem with major, high-profile sites such as <citetitle>Google</citetitle>,
1652 <citetitle>Yahoo</citetitle>, etc. Any site with global or regional reach,
1653 has a good chance of being a candidate. But at the other end of the spectrum
1654 are any number of smaller, low-profile sites such as for local clubs or
1655 schools. Since their reach and impact are much less, they are best handled by
1656 inclusion in the user's <filename>user.action</filename>, and thus would be
1657 unlikely to be included.
1663 <sect2 renderas="sect3" id="noonecares"><title>Why doesn't anyone answer my support
1666 Rest assured that it has been read and considered. Why it is not answered,
1667 could be for various reasons, including no one has a good answer for it, no
1668 one has had time to yet investigate it thoroughly, it has been reported
1669 numerous times already, or because not enough information was provided to help
1670 us help you. Your efforts are not wasted, and we do appreciate them.
1676 <sect2 renderas="sect3" id="ip"><title>How can I hide my IP address?</title>
1678 If you run both the browser and &my-app; locally, you cannot hide your IP
1679 address with <application>Privoxy</application> or ultimately any other
1680 software alone. The server needs to know your IP address so that it knows
1681 where to send the responses back.
1684 There are many publicly usable "anonymous" proxies out there, which
1685 provide a further level of indirection between you and the web server.
1688 However, these proxies are called "anonymous" because you don't need
1689 to authenticate, not because they would offer any real anonymity.
1690 Most of them will log your IP address and make it available to the
1691 authorities in case you violate the law of the country they run in. In fact
1692 you can't even rule out that some of them only exist to *collect* information
1693 on (those suspicious) people with a more than average preference for privacy.
1696 If you want to hide your IP address from most adversaries,
1697 you should consider chaining <application>Privoxy</application>
1698 with <ulink url="https://www.torproject.org/">Tor</ulink>.
1699 The configuration details can be found in
1700 <ulink url="#TOR">How do I use <application>Privoxy</application> together
1701 with <application>Tor</application> section</ulink>
1706 <sect2 renderas="sect3" id="anonforsure">
1707 <title>Can Privoxy guarantee I am anonymous?</title>
1709 No. Your chances of remaining anonymous are improved, but unless you
1710 <ulink url="#TOR">chain <application>Privoxy</application> with <application>Tor</application></ulink>
1711 or a similar proxy and know what you're doing when it comes to configuring
1712 the rest of your system, you should assume that everything you do
1713 on the Web can be traced back to you.
1716 <application>Privoxy</application> can remove various information about you,
1717 and allows <emphasis>you</emphasis> more freedom to decide which sites
1718 you can trust, and what details you want to reveal. But it neither
1719 hides your IP address, nor can it guarantee that the rest of the system
1720 behaves correctly. There are several possibilities how a web sites can find
1721 out who you are, even if you are using a strict <application>Privoxy</application>
1722 configuration and chained it with <application>Tor</application>.
1725 Most of <application>Privoxy's</application> privacy-enhancing features can be easily subverted
1726 by an insecure browser configuration, therefore you should use a browser that can
1727 be configured to only execute code from trusted sites, and be careful which sites you trust.
1728 For example there is no point in having <application>Privoxy</application>
1729 modify the User-Agent header, if websites can get all the information they want
1730 through JavaScript, ActiveX, Flash, Java etc.
1733 A few browsers disclose the user's email address in certain situations, such
1734 as when transferring a file by FTP. <application>Privoxy</application>
1735 does not filter FTP. If you need this feature, or are concerned about the
1736 mail handler of your browser disclosing your email address, you might
1737 consider products such as <application>NSClean</application>.
1740 Browsers available only as binaries could use non-standard headers to give
1741 out any information they can have access to: see the manufacturer's license
1742 agreement. It's impossible to anticipate and prevent every breach of privacy
1743 that might occur. The professionally paranoid prefer browsers available as
1744 source code, because anticipating their behavior is easier. Trust the source,
1750 <sect2 renderas="sect3" id="proxytest">
1751 <title>A test site says I am not using a Proxy.</title>
1753 Good! Actually, they are probably testing for some other kinds of proxies.
1754 Hiding yourself completely would require additional steps.
1758 <sect2 renderas="sect3" id="tor"><title>How do I use Privoxy
1759 together with Tor?</title>
1761 Before you configure <application>Privoxy</application> to use
1762 <ulink url="https://www.torproject.org/">Tor</ulink>,
1763 please follow the <citetitle>User Manual</citetitle> chapters
1764 <ulink url="../user-manual/installation.html">2. Installation</ulink> and
1765 <ulink url="../user-manual/startup.html">5. Startup</ulink> to make sure
1766 <application>Privoxy</application> itself is setup correctly.
1769 If it is, refer to <ulink url="https://www.torproject.org/documentation.html">Tor's
1770 extensive documentation</ulink> to learn how to install <application>Tor</application>,
1771 and make sure <application>Tor</application>'s logfile says that
1772 <quote>Tor has successfully opened a circuit</quote> and it
1773 <quote>looks like client functionality is working</quote>.
1776 If either <application>Tor</application> or <application>Privoxy</application>
1777 isn't working, their combination most likely will neither. Testing them on their
1778 own will also help you to direct problem reports to the right audience.
1779 If <application>Privoxy</application> isn't working, don't bother the
1780 <application>Tor</application> developers. If <application>Tor</application>
1781 isn't working, don't send bug reports to the <application>Privoxy</application> Team.
1784 If you verified that <application>Privoxy</application> and <application>Tor</application>
1785 are working, it is time to connect them. As far as <application>Privoxy</application>
1786 is concerned, <application>Tor</application> is just another proxy that can be reached
1787 by socks4, socks4a and socks5. Most likely you are interested in <application>Tor</application>
1788 to increase your anonymity level, therefore you should use socks5, to make sure DNS
1789 requests are done through <application>Tor</application> and thus invisible to your
1790 local network. Using socks4a would work too, but with socks5 you get more precise error
1795 <application>Privoxy's</application>
1796 <ulink url="../user-manual/config.html">main configuration file</ulink>
1797 is already prepared for <application>Tor</application>, if you are using a
1798 default <application>Tor</application> configuration and run it on the same
1799 system as &my-app;, you just have to edit the
1800 <ulink url="../user-manual/config.html#FORWARDING">forwarding section</ulink>
1801 and uncomment the line:
1804 # forward-socks5t / 127.0.0.1:9050 .
1807 Note that if you got Tor through one of the bundles, you may
1808 have to change the port from 9050 to 9150 (or even another one).
1809 For details, please check the documentation on the
1810 <ulink url="https://torproject.org/">Tor website</ulink>.
1814 This is enough to reach the Internet, but additionally you might want to
1815 uncomment the following forward rules, to make sure your local network is still
1816 reachable through Privoxy:
1819 # forward 192.168.*.*/ .
1820 # forward 10.*.*.*/ .
1821 # forward 127.*.*.*/ .
1824 Unencrypted connections to systems in these address ranges will
1825 be as (un)secure as the local network is, but the alternative is
1826 that your browser can't reach the network at all. Then again,
1827 that may actually be desired and if you don't know for sure
1828 that your browser has to be able to reach the local network,
1829 there's no reason to allow it.
1832 If you want your browser to be able to reach servers in your local
1833 network by using their names, you will need additional exceptions
1834 that look like this:
1837 # forward localhost/ .
1840 Save the modified configuration file and open
1841 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1842 in your browser, confirm that <application>Privoxy</application> has reloaded its configuration
1843 and that there are no other forward lines, unless you know that you need them. If everything looks good,
1845 <ulink url="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#IsMyConnectionPrivate">Tor
1846 Faq 4.2</ulink> to learn how to verify that you are really using <application>Tor</application>.
1849 Afterward, please take the time to at least skim through the rest
1850 of <application>Tor's</application> documentation. Make sure you understand
1851 what <application>Tor</application> does, why it is no replacement for
1852 application level security, and why you probably don't want to
1853 use it for unencrypted logins.
1857 <sect2 renderas="sect3" id="sitebreak">
1858 <title>Might some things break because header information or
1859 content is being altered?</title>
1862 Definitely. It is common for sites to use browser type, browser version,
1863 HTTP header content, and various other techniques in order to dynamically
1864 decide what to display and how to display it. What you see, and what I see,
1865 might be very different. There are many, many ways that this can be handled,
1866 so having hard and fast rules, is tricky.
1870 The <quote>User-Agent</quote> is sometimes used in this way to identify
1871 the browser, and adjust content accordingly.
1875 Also, different browsers use different encodings of non-English
1876 characters, certain web servers convert pages on-the-fly according to the
1877 User Agent header. Giving a <quote>User Agent</quote> with the wrong
1878 operating system or browser manufacturer causes some sites in these languages
1879 to be garbled; Surfers to Eastern European sites should change it to
1880 something closer. And then some page access counters work by looking at the
1881 <quote>Referer</quote> header; they may fail or break if unavailable. The
1882 weather maps of Intellicast have been blocked by their server when no
1883 <quote>Referer</quote> or cookie is provided, is another example. (But you
1884 can forge both headers without giving information away). There are
1885 many other ways things can go wrong when trying to fool a web server. The
1886 results of which could inadvertently cause pages to load incorrectly,
1887 partially, or even not at all. And there may be no obvious clues as to just
1888 what went wrong, or why. Nowhere will there be a message that says
1889 <quote><emphasis>Turn off <literal>fast-redirects</literal> or else!</emphasis>
1894 Similar thoughts apply to modifying JavaScript, and, to a lesser degree,
1899 If you have problems with a site, you will have to adjust your configuration
1900 accordingly. Cookies are probably the most likely adjustment that may
1901 be required, but by no means the only one.
1907 <sect2 renderas="sect3" id="caching">
1908 <title>Can Privoxy act as a <quote>caching</quote> proxy to
1909 speed up web browsing?</title>
1911 No, it does not have this ability at all. You want something like
1912 <ulink url="http://www.squid-cache.org/">Squid</ulink> or
1913 <ulink url="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</ulink> for this.
1914 And, yes, before you ask, <application>Privoxy</application> can co-exist
1915 with other kinds of proxies like <application>Squid</application>.
1916 See the <ulink url="../user-manual/config.html#FORWARDING">forwarding
1917 chapter</ulink> in the <ulink url="../user-manual/index.html">user
1918 manual</ulink> for details.
1922 <sect2 renderas="sect3" id="firewall">
1923 <title>What about as a firewall? Can Privoxy protect me?</title>
1925 Not in the way you mean, or in the way some firewall vendors claim they can.
1926 <application>Privoxy</application> can help protect your privacy, but can't
1927 protect your system from intrusion attempts. It is, of course, perfectly possible
1928 to use <emphasis>both</emphasis>.
1932 <sect2 renderas="sect3" id="wasted">
1933 <title>I have large empty spaces / a checkerboard pattern now where
1934 ads used to be. Why?</title>
1936 It is technically possible to eliminate banners and ads in a way that frees
1937 their allocated page space. This could easily be done by blocking with
1938 <application>Privoxy's</application> filters,
1939 and eliminating the <emphasis>entire</emphasis> image references from the
1943 But, this would consume considerably more CPU resources (IOW, slow things
1944 down), would likely destroy the layout of some web pages which rely on the
1945 banners utilizing a certain amount of page space, and might fail in other
1946 cases, where the screen space is reserved (e.g. by HTML tables for instance).
1947 Also, making ads and banners disappear without any trace complicates
1948 troubleshooting, and would sooner or later be problematic.
1951 The better alternative is to instead let them stay, and block the resulting
1952 requests for the banners themselves as is now the case. This leaves either
1953 empty space, or the familiar checkerboard pattern.
1956 So the developers won't support this in the default configuration, but you
1957 can of course define appropriate filters yourself to achieve this.
1961 <sect2 renderas="sect3" id="ssl">
1962 <title>How can Privoxy filter Secure (HTTPS) URLs?</title>
1965 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
1966 <application>Privoxy</application> will impersonate the destination
1967 server and can thus filter encrypted requests and responses as well.
1971 <ulink url="../user-manual/actions-file.html#HTTPS-INSPECTION">https-inspection</ulink>
1972 secure HTTP connections are encrypted SSL sessions between your
1973 browser and the secure site, and there is little
1974 that <application>Privoxy</application> can do but hand the raw
1975 gibberish data though from one end to the other unprocessed.
1978 The only exception to this is blocking by host patterns, as the client needs
1979 to tell <application>Privoxy</application> the name of the remote server,
1980 so that <application>Privoxy</application> can establish the connection.
1981 If that name matches a host-only pattern, the connection will be blocked.
1984 As far as ad blocking is concerned, this is less of a restriction than it may
1985 seem, since ad sources are often identifiable by the host name, and often
1986 the banners to be placed in an encrypted page come unencrypted nonetheless
1987 for efficiency reasons, which exposes them to the full power of
1988 <application>Privoxy</application>'s ad blocking.
1991 <quote>Content cookies</quote> (those that are embedded in the actual HTML or
1992 JS page content, see <literal><ulink
1993 url="../user-manual/actions-file.html#FILTER-CONTENT-COOKIES">filter{content-cookies}</ulink></literal>),
1994 in an SSL transaction will be impossible to block under these conditions.
1995 Fortunately, this does not seem to be a very common scenario since most
1996 cookies come by traditional means.
2001 <sect2 renderas="sect3" id="http2">
2002 <title>Does Privoxy support HTTP/2?</title>
2004 Privoxy currently doesn't parse HTTP/2 but applications
2005 can tunnel HTTP/2 through Privoxy if Privoxy is configured
2006 to allow CONNECT requests (default) which are also used
2010 Adding HTTP/2 support is on the
2011 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=blob_plain;f=TODO;hb=HEAD">TODO</ulink>
2012 list but currently nobody is known to work on it.
2016 <sect2 renderas="sect3" id="secure">
2017 <title>Privoxy runs as a <quote>server</quote>. How
2018 secure is it? Do I need to take any special precautions?</title>
2020 On Unix-like systems, <application>Privoxy</application> can run as a non-privileged
2021 user, which is how we recommend it be run. Also, by default
2022 <application>Privoxy</application> listens to requests from <quote>localhost</quote>
2026 The server aspect of <application>Privoxy</application> is not itself directly
2027 exposed to the Internet in this configuration. If you want to have
2028 <application>Privoxy</application> serve as a LAN proxy, this will have to
2029 be opened up to allow for LAN requests. In this case, we'd recommend
2030 you specify only the LAN gateway address, e.g. 192.168.1.1, in the main
2031 <application>Privoxy</application> configuration file and check all <ulink
2032 url="../user-manual/config.html#ACCESS-CONTROL">access control and security
2033 options</ulink>. All LAN hosts can then use this as their proxy address
2034 in the browser proxy configuration, but <application>Privoxy</application>
2035 will not listen on any external interfaces. ACLs can be defined in addition,
2036 and using a firewall is always good too. Better safe than sorry.
2041 <sect2 renderas="sect3" id="turnoff">
2042 <title>Can I temporarily disable Privoxy?</title>
2044 &my-app; doesn't have a transparent proxy mode,
2045 but you can toggle off blocking and content filtering.
2048 The easiest way to do that is to point your browser
2049 to the remote toggle URL: <ulink
2050 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>.
2053 See the <ulink url="../user-manual/appendix.html#BOOKMARKLETS">Bookmarklets section</ulink>
2054 of the <citetitle>User Manual</citetitle> for an easy way to access this
2055 feature. Note that this is a feature that may need to be enabled in the main
2056 <filename>config</filename> file.
2061 <sect2 renderas="sect3" id="reallyoff">
2062 <title>When <quote>disabled</quote> is Privoxy totally
2063 out of the picture?</title>
2065 No, this just means all optional filtering and actions are disabled.
2066 <application>Privoxy</application> is still acting as a proxy, but just
2067 doing less of the things that <application>Privoxy</application> would
2068 normally be expected to do. It is still a <quote>middle-man</quote> in
2069 the interaction between your browser and web sites. See below to bypass
2074 <sect2 renderas="sect3" id="turnoff2">
2075 <title>How can I tell Privoxy to totally ignore certain sites?</title>
2077 Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser
2078 configuration issue, not a &my-app; issue. Modern browsers typically do have
2079 settings for not proxying certain sites. Check your browser's help files.
2084 <sect2 renderas="sect3" id="crunch">
2085 <title>My logs show Privoxy <quote>crunches</quote>
2086 ads, but also its own internal CGI pages. What is a <quote>crunch</quote>?</title>
2088 A <quote>crunch</quote> means <application>Privoxy</application> intercepted
2089 <emphasis>something</emphasis>, nothing more. Often this is indeed ads or
2090 banners, but <application>Privoxy</application> uses the same mechanism for
2091 trapping requests for its own internal pages. For instance, a request for
2092 <application>Privoxy's</application> configuration page at: <ulink
2093 url="http://config.privoxy.org">http://config.privoxy.org</ulink>, is
2094 intercepted (i.e. it does not go out to the 'net), and the familiar CGI
2095 configuration is returned to the browser, and the log consequently will show
2096 a <quote>crunch</quote>.
2099 Since version 3.0.7, Privoxy will also log the crunch reason.
2100 If you are using an older version you might want to upgrade.
2104 <sect2 renderas="sect3" id="downloads">
2105 <title>Can Privoxy affect files that I download
2106 from a webserver? FTP server?</title>
2108 From the webserver's perspective, there is no difference between
2109 viewing a document (i.e. a page), and downloading a file. The same is true of
2110 <application>Privoxy</application>. If there is a match for a <literal><ulink
2111 url="../user-manual/actions-file.html#BLOCK">block</ulink></literal> pattern,
2112 it will still be blocked, and of course this is obvious.
2115 Filtering is potentially more of a concern since the results are not always
2116 so obvious, and the effects of filtering are there whether the file is simply
2117 viewed, or downloaded. And potentially whether the content is some obnoxious
2118 advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course,
2119 one of these presumably is <quote>bad</quote> content that we don't want, and
2120 the other is <quote>good</quote> content that we do want.
2121 <application>Privoxy</application> is blind to the differences, and can only
2122 distinguish <quote>good from bad</quote> by the configuration parameters
2123 <emphasis>we</emphasis> give it.
2126 <application>Privoxy</application> knows the differences in files according
2127 to the <quote>Content Type</quote> as reported by the webserver. If this is
2128 reported accurately (e.g. <quote>application/zip</quote> for a zip archive),
2129 then <application>Privoxy</application> knows to ignore these where
2130 appropriate. <application>Privoxy</application> potentially can filter HTML
2131 as well as plain text documents, subject to configuration parameters of
2132 course. Also, documents that are of an unknown type (generally assumed to be
2133 <quote>text/plain</quote>) can be filtered, as will those that might be
2134 incorrectly reported by the webserver. If such a file is a downloaded file
2135 that is intended to be saved to disk, then any content that might have been
2136 altered by filtering, will be saved too, for these (probably rare) cases.
2139 Note that versions later than 3.0.2 do NOT filter document types reported as
2140 <quote>text/plain</quote>. Prior to this, <application>Privoxy</application>
2141 did filter this document type.
2144 In short, filtering is <quote>ON</quote> if a) the content type as reported
2145 by the webserver is appropriate <emphasis>and</emphasis> b) the configuration
2146 allows it (or at least does not disallow it). That's it. There is no magic
2147 cookie anywhere to say this is <quote>good</quote> and this is
2148 <quote>bad</quote>. It's the configuration that lets it all happen or not.
2151 If you download text files, you probably do not want these to be filtered,
2152 particularly if the content is source code, or other critical content. Source
2153 code sometimes might be mistaken for Javascript (i.e. the kind that might
2154 open a pop-up window). It is recommended to turn off filtering for download
2155 sites (particularly if the content may be plain text files and you are using
2156 version 3.0.2 or earlier) in your <filename>user.action</filename> file. And
2157 also, for any site or page where making <emphasis>any</emphasis> changes at
2158 all to the content is to be avoided.
2161 <application>Privoxy</application> does not do FTP at all, only HTTP
2162 and HTTPS (SSL) protocols.
2166 <sect2 renderas="sect3" id="downloads2">
2167 <title>I just downloaded a Perl script, and Privoxy
2168 altered it! Yikes, what is wrong!</title>
2174 <sect2 renderas="sect3" id="hostsfile">
2175 <title>Should I continue to use a <quote>HOSTS</quote> file for ad-blocking?</title>
2177 One time-tested technique to defeat common ads is to trick the local DNS
2178 system by giving a phony IP address for the ad generator in the local
2179 <filename>HOSTS</filename> file, typically using <literal>127.0.0.1</literal>, aka
2180 <literal>localhost</literal>. This effectively blocks the ad.
2183 There is no reason to use this technique in conjunction with
2184 <application>Privoxy</application>. <application>Privoxy</application>
2185 does essentially the same thing, much more elegantly and with much more
2186 flexibility. A large <filename>HOSTS</filename> file, in fact, not only
2187 duplicates effort, but may get in the way and seriously slow down your system.
2188 It is recommended to remove such entries from your <filename>HOSTS</filename> file. If you think
2189 your hosts list is neglected by <application>Privoxy's </application>
2190 configuration, consider adding your list to your <filename>user.action</filename> file:
2196 ads.galore.example.com
2197 etc.example.com</screen>
2200 <sect2 renderas="sect3" id="seealso">
2201 <title>Where can I find more information about Privoxy
2202 and related issues?</title>
2203 <!-- Include seealso.sgml boilerplate: -->
2205 <!-- end boilerplate -->
2210 <ulink url="../user-manual/seealso.html">user-manual</ulink> for
2216 <sect2 renderas="sect3" id="microsuck">
2217 <title>I've noticed that Privoxy changes <quote>Microsoft</quote> to
2218 <quote>MicroSuck</quote>! Why are you manipulating my browsing?</title>
2221 We're not. The text substitutions that you are seeing are disabled
2222 in the default configuration as shipped. You have either manually
2223 activated the <quote><literal>fun</literal></quote> filter which
2224 is clearly labeled <quote>Text replacements for subversive browsing
2225 fun!</quote> or you are using an older Privoxy version and have implicitly
2226 activated it by choosing the <quote>Advanced</quote> profile in the
2227 web-based editor. Please upgrade.
2231 <sect2 renderas="sect3" id="valid">
2232 <title>Does Privoxy produce <quote>valid</quote> HTML (or XHTML)?</title>
2235 Privoxy generates HTML in both its own <quote>templates</quote>, and possibly
2236 whenever there are text substitutions via a &my-app; filter. While this
2237 should always conform to the HTML 4.01 specifications, it has not been
2238 validated against this or any other standard.
2242 <sect2 renderas="sect3" id="surprise-privoxy">
2243 <title>How did you manage to get Privoxy on my computer without my consent?</title>
2246 We didn't. We make Privoxy available for download, but we don't go
2247 around installing it on other people's systems behind their back.
2248 If you discover Privoxy running on your system and are sure you didn't
2249 install it yourself, somebody else did. You may not even be running
2250 the real Privoxy, but maybe something else that only pretends to be
2251 Privoxy, or maybe something that is based on the real Privoxy,
2252 but has been modified.
2255 Lately there have been reports of problems with some kind of
2256 "parental control" software based on Privoxy that came preinstalled on
2257 certain <ulink url="https://sourceforge.net/p/ijbswa/bugs/813/">ASUS Netbooks</ulink>.
2258 The problems described are inconsistent with the behaviour of official
2259 Privoxy versions, which suggests that the preinstalled software may
2260 contain vendor modifications that we don't know about and thus can't debug.
2263 Privoxy's <link linkend="copyright">license</link> allows vendor
2264 modifications, but the vendor has to comply with the license,
2265 which involves informing the user about the changes and to make
2266 the changes available under the same license as Privoxy itself.
2269 If you are having trouble with a modified Privoxy version,
2270 please try to talk to whoever made the modifications before
2271 reporting the problem to us. Please also try to convince
2272 whoever made the modifications to talk to us. If you think
2273 somebody gave you a modified Privoxy version without complying
2274 to the license, please let us know.
2282 <!-- ~~~~~ New section ~~~~~ -->
2284 <sect1 id="trouble">
2285 <title>Troubleshooting</title>
2287 <sect2 renderas="sect3" id="refused">
2288 <title>I cannot connect to any websites. Or, I am getting
2289 <quote>connection refused</quote> message with every web page. Why?</title>
2291 There are several possibilities:
2295 <application>Privoxy</application> is not running. Solution: verify
2296 that &my-app; is installed correctly, has not crashed, and is indeed running.
2297 Turn on <application>Privoxy's</application> logging, and look at the logs to see what they say.
2299 <listitem><para>Or your browser is configured for a different port than what
2300 <application>Privoxy</application> is using. Solution: verify that &my-app;
2301 and your browser are set to the same port (<literal>listen-address</literal>).
2303 <listitem><para>Or if using a forwarding rule, you have a configuration problem or a
2304 problem with a host in the forwarding chain. Solution: temporarily alter your
2305 configuration and take the forwarders out of the equation.
2308 Or you have a firewall that is interfering and blocking you. Solution:
2309 try disabling or removing the firewall as a simple test.
2315 <!-- ~~~~~ New section ~~~~~ -->
2316 <sect2 renderas="sect3" id="error503">
2317 <title>Why am I getting a 503 Error (WSAECONNREFUSED) on every page?</title>
2319 More than likely this is a problem with your TCP/IP networking. ZoneAlarm has
2320 been reported to cause this symptom -- even if not running! The solution is
2321 to either fight the ZA configuration, or uninstall ZoneAlarm, and then find
2322 something better behaved in its place. Other personal firewall type products
2323 may cause similar type problems if not configured correctly.
2327 <sect2 renderas="sect3" id="flushit">
2328 <title>I just added a new rule, but the steenkin ad is
2329 still getting through. How?</title>
2331 If the ad had been displayed before you added its URL, it will probably be
2332 held in the browser's cache for some time, so it will be displayed without
2333 the need for any request to the server, and <application>Privoxy</application>
2334 will not be involved. Flush the browser's caches, and then try again.
2338 If this doesn't help, you probably have an error in the rule you
2339 applied. Try pasting the full URL of the offending ad into <ulink
2340 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2341 and see if it really matches your new rule. Blocking ads is like blocking
2342 spam: a lot of tinkering is required to stay ahead of the game. And
2343 remember you need to block the URL of the ad in question, which may be
2344 entirely different from the site URL itself. Most ads are hosted on different
2345 servers than the main site itself. If you right-click on the ad, you should
2346 be able to get all the relevant information you need. Alternately, you can
2347 find the correct URL by looking at <application>Privoxy's</application> logs
2348 (you may need to enable logging in the main config file if its disabled).
2351 Below is a slightly modified real-life log snippet that originates with one
2352 requested URL: <literal>www.example.com</literal> (name of site was changed
2353 for this example, the number of requests is real). You can see in this the
2354 complexity of what goes into making up this one <quote>page</quote>. There
2355 are eight different domains involved here, with thirty two separate URLs
2356 requested in all, making up all manner of images, Shockwave Flash,
2357 JavaScript, CSS stylesheets, scripts, and other related content. Some of this
2358 content is obviously <quote>good</quote> or <quote>bad</quote>, but not all.
2359 Many of the more questionable looking requests, are going to outside domains
2360 that seem to be identifying themselves with suspicious looking names, making
2361 our job a little easier. &my-app; has <quote>crunched</quote> (meaning caught
2362 and BLOCKED) quite a few items in this example, but perhaps missed a few as well.
2366 Request: www.example.com/
2367 Request: www.example.com/favicon.ico
2368 Request: img.example.com/main.css
2369 Request: img.example.com/sr.js
2370 Request: example.betamarker.com/example.html
2371 Request: www.lik-sang.com/Banners/bestsellers/skyscraper.php?likref=BSellers
2372 Request: img.example.com/pb.png
2373 Request: www.google-analytics.com/urchin.js crunch! (Blocked)
2374 Request: www.advertising-department.com/ats/switch.ps.php?26856 crunch! (Blocked)
2375 Request: img.example.com/p.gif
2376 Request: www.popuptraffic.com/assign.php?l=example&mode=behind crunch! (Blocked)
2377 Request: www.popuptraffic.com/scripts/popup.php?hid=5c3cf&tmpl=PBa.tmpl crunch! (Blocked)
2378 Request: www.popuptraffic.com/assign.php?l=example crunch! (Blocked)
2379 Request: www.lik-sang.com/Banners/best_sellers/best_sellers.css
2380 Request: www.adtrak.net/adx.js crunch! (Blocked)
2381 Request: img.example.com/hbg.gif
2382 Request: img.example.com/example.jpg
2383 Request: img.example.com/mt.png
2384 Request: img.example.com/mm.png
2385 Request: img.example.com/mb.png
2386 Request: www.popuptraffic.com/scripts/popup.php?hid=a71b91fa5&tmpl=Ua.tmp crunch! (Blocked)
2387 Request: www.example.com/tracker.js
2388 Request: www.lik-sang.com/Banners/best_sellers/lsi_head.gif
2389 Request: www.adtrak.net/adjs.php?n=020548130&what=zone:61 crunch! (Blocked)
2390 Request: www.adtrak.net/adjs.php?n=463594413&what=zone:58&source=Ua crunch! (Blocked)
2391 Request: www.lik-sang.com/Banners/best_sellers/bottomani.swf
2392 Request: mmm.elitemediagroup.net/install.php?allowpop=no&popupmincook=0&allowsp2=1 crunch! (Blocked)
2393 Request: www.example.com/tracker.js?screen=1400x1050&win=962x693
2394 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=61 crunch! (Blocked)
2395 Request: 66.70.21.80/scripts/click.php?hid=5c3cf599a9efd0320d26&si
2396 Request: 66.70.21.80/img/pixel.gif
2397 Request: www.adtrak.net/adlog.php?bannerid=1309&clientid=439&zoneid=58&source=Ua&block=86400 crunch! (Blocked)
2398 Request: 66.70.21.80/scripts/click.php?hid=a71b9f6504b0c5681fa5&si=Ua
2402 Despite 12 out of 32 requests being blocked, the page looked, and seemed to
2403 behave perfectly <quote>normal</quote> (minus some ads, of course).
2408 <sect2 renderas="sect3" id="badsite">
2409 <title>One of my favorite sites does not work with Privoxy.
2410 What can I do?</title>
2413 First verify that it is indeed a <application>Privoxy</application> problem,
2414 by toggling off <application>Privoxy</application> through <ulink
2415 url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
2416 (the toggle feature may need to be enabled in the main
2417 <filename>config</filename>),
2418 and then shift-reloading the problem page (i.e. holding down the shift key
2419 while clicking reload. Alternatively, flush your browser's disk and memory
2424 If the problem went away, we know we have a configuration related problem.
2426 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
2427 and paste the full URL of the page in question into the prompt. See which
2428 actions are being applied to the URL, and which matches in which actions
2429 files are responsible for that. It might be helpful also to look at your logs
2430 for this site too, to see what else might be happening (note: logging may need
2431 to be enabled in the main config file). Many sites are
2432 complex and require a number of related pages to help present their content.
2433 Look at what else might be used by the page in question, and what of that
2434 might be <emphasis>required</emphasis>.
2435 Now, armed with this information, go to
2437 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2438 and select the appropriate actions files for editing. </para>
2440 You can now either look for a section which disables the actions that
2441 you suspect to cause the problem and add a pattern for your site there,
2442 or make up a completely new section for your site. In any case, the recommended
2443 way is to disable only the prime suspect, reload the problem page, and only
2444 if the problem persists, disable more and more actions until you have
2445 identified the culprit. You may or may not want to turn the other actions
2446 on again. Remember to flush your browser's caches in between any such changes!
2449 Alternately, if you are comfortable with a text editor, you can accomplish
2450 the same thing by editing the appropriate actions file. Probably the easiest
2451 way to deal with such problems when editing by hand is to add your
2452 site to a <literal>{ fragile }</literal> section in <filename>user.action</filename>,
2453 which is an alias that turns off most <quote>dangerous</quote>
2454 actions, but is also likely to turn off more actions then needed, and thus lower
2455 your privacy and protection more than necessary,
2458 Troubleshooting actions is discussed in more detail in the <ulink
2459 url="../user-manual/appendix.html#ACTIONSANAT">User Manual appendix,
2460 Troubleshooting: the Anatomy of an Action</ulink>.
2461 There is also an <ulink
2462 url="../user-manual/actions-file.html#ACT-EXAMPLES">actions tutorial</ulink>
2463 with general configuration information and examples.
2466 As a last resort, you can always see if your browser has a setting that will
2467 bypass the proxy setting for selective sites. Modern browsers can do this.
2473 <!-- ~~~~~ New section ~~~~~ -->
2474 <sect2 id="dun" renderas="sect3">
2475 <title>After installing Privoxy, I have to log in
2476 every time I start IE. What gives?</title>
2479 This is a quirk that affects the installation of
2480 <application>Privoxy</application>, in conjunction with Internet Explorer and
2481 Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may
2482 appear to be corrupted or invalid DUN settings, or passwords.
2486 When setting up an NT based Windows system with
2487 <application>Privoxy</application> you may find that things do not seem to be
2488 doing what you expect. When you set your system up you will probably have set
2489 up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when
2490 logged in with administrator privileges. You will probably have made this DUN
2491 connection available to other accounts that you may have set-up on your
2492 system. E.g. Mum or Dad sets up the system and makes accounts suitably
2493 configured for the kids.
2497 When setting up <application>Privoxy</application> in this environment you
2498 will have to alter the proxy set-up of Internet Explorer (IE) for the
2499 specific DUN connection on which you wish to use
2500 <application>Privoxy</application>. When you do this the ICS DUN set-up
2501 becomes user specific. In this instance you will see no difference if you
2502 change the DUN connection under the account used to set-up the connection.
2503 However when you do this from another user you will notice that the DUN
2504 connection changes to make available to "Me only". You will also find that
2505 you have to store the password under each different user!
2509 The reason for this is that each user's set-up for IE is user specific. Each
2510 set-up DUN connection and each LAN connection in IE store the settings for
2511 each user individually. As such this enforces individual configurations
2512 rather than common ones. Hence the first time you use a DUN connection after
2513 re-booting your system it may not perform as you expect, and prompt you for
2514 the password. Just set and save the password again and all should be OK.
2518 [Thanks to Ray Griffith for this submission.]
2523 <!-- ~~~~~ New section ~~~~~ -->
2524 <sect2 id="ftp" renderas="sect3">
2525 <title>I cannot connect to any FTP sites. Privoxy
2526 is blocking me.</title>
2528 <application>Privoxy</application> cannot act as a proxy for FTP traffic,
2529 so do not configure your browser to use <application>Privoxy</application>
2530 as an FTP proxy. The same is true for <emphasis>any protocol other than HTTP
2531 or HTTPS (SSL)</emphasis>.
2534 Most browsers understand FTP as well as HTTP. If you connect to a site, with
2535 a URL like <literal>ftp://ftp.example.com</literal>, your browser is making
2536 an FTP connection, and not a HTTP connection. So while your browser may
2537 speak FTP, <application>Privoxy</application> does not, and cannot proxy
2541 To complicate matters, some systems may have a generic <quote>proxy</quote>
2542 setting, which will enable various protocols, including
2543 <emphasis>both</emphasis> HTTP and FTP proxying! So it is possible to
2544 accidentally enable FTP proxying in these cases. And of course, if this
2545 happens, <application>Privoxy</application> will indeed cause problems since
2546 it does not know FTP. <![%p-newstuff;[Newer version will give a sane error
2547 message if a FTP connection is attempted.]]> Just disable the FTP setting
2548 and all will be well again.
2551 Will <application>Privoxy</application> ever proxy FTP traffic? Unlikely.
2552 There just is not much reason, and the work to make this happen is more than
2557 <!-- ~~~~~ New section ~~~~~ -->
2558 <sect2 id="macosxie" renderas="sect3">
2559 <title>In Mac OS X, I can't configure Microsoft Internet Explorer to use
2560 Privoxy as the HTTP proxy.</title>
2562 Microsoft Internet Explorer (in versions like 5.1) respects system-wide
2563 network settings. In order to change the HTTP proxy, open System
2564 Preferences, and click on the Network icon. In the settings pane that
2565 comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox
2566 is checked and enter <literal>127.0.0.1</literal> in the entry field.
2567 Enter <literal>8118</literal> in the Port field. The next time you start
2568 IE, it should reflect these values.
2572 <!-- ~~~~~ New section ~~~~~ -->
2573 <sect2 renderas="sect3" id="macosxuninstall">
2574 <title>In Mac OS X, I dragged the Privoxy folder to the trash in order to
2575 uninstall it. Now the finder tells me I don't have sufficient privileges to
2576 empty the trash.</title>
2578 Note: This ONLY applies to privoxy 3.0.6 and earlier.
2581 Just dragging the <application>Privoxy</application> folder to the trash is
2582 not enough to delete it. <application>Privoxy</application> supplies an
2583 <application>uninstall.command</application> file that takes care of
2584 these details. Open the trash, drag the <application>uninstall.command</application>
2585 file out of the trash and double-click on it. You will be prompted for
2586 confirmation and the administration password.
2589 The trash may still appear full after this command; emptying the trash
2590 from the desktop should make it appear empty again.
2594 <!-- ~~~~~ New section ~~~~~ -->
2595 <sect2 renderas="sect3" id="macosximages">
2596 <title>In Mac OS X Panther (10.3), images often fail to load and/or I
2597 experience random delays in page loading. I'm using
2598 <literal>localhost</literal> as my browser's proxy setting.</title>
2600 We believe this is due to an IPv6-related bug in Mac OS X, but don't fully
2601 understand the issue yet. In any case, changing the proxy setting to
2602 <literal>127.0.0.1</literal> instead of <literal>localhost</literal>
2603 works around the problem.
2607 <!-- ~~~~~ New section ~~~~~ -->
2608 <sect2 renderas="sect3" id="macosxaccountdeletion">
2609 <title>I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped
2612 The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS
2613 X deletes all user accounts that are either not part of OS X itself or are
2614 not interactive user accounts (ones you log in with). Since, for the sake of
2615 security, &my-app; runs as a non-privileged user that is created by its
2616 installer (_privoxy), it can no longer start up once that account gets deleted.
2617 The solution is to perform a complete uninstall using the supplied
2618 <application>uninstall.command</application> script (either back up your
2619 configuration files or select to not have the uninstaller remove them when it
2620 prompts you) and then reinstall &my-app; using the installer package and merge
2621 in your configuration.
2625 <sect2 renderas="sect3" id="nohostname">
2626 <title>My logs show many <quote>Unable to get my own hostname</quote> lines.
2629 <application>Privoxy</application> tries to get the hostname of the system
2630 its running on from the IP address of the system interface it is bound to
2631 (from the <filename>config</filename> file
2632 <emphasis>listen-address</emphasis> setting). If the system cannot supply
2633 this information, <application>Privoxy</application> logs this condition.
2636 Typically, this would be considered a minor system configuration error. It is
2637 not a fatal error to <application>Privoxy</application> however, but may
2638 result in a much slower response from <application>Privoxy</application> on
2639 some platforms due to DNS timeouts.
2642 This can be caused by a problem with the local <filename>hosts</filename>
2643 file. If this file has been changed from the original, try reverting it to
2644 see if that helps. Make sure whatever name(s) are used for the local system,
2645 that they resolve both ways.
2648 You should also be able to work around the problem with the
2649 <ulink url="../user-manual/config.html#HOSTNAME">hostname option</ulink>.
2653 <sect2 renderas="sect3" id="inuse">
2654 <title>When I try to launch Privoxy, I get an
2655 error message <quote>port 8118 is already in use</quote> (or similar wording).
2658 Port 8118 is <application>Privoxy's</application> default TCP
2659 <quote>listening</quote> port. Typically this message would mean that there
2660 is already one instance of <application>Privoxy</application> running, and
2661 your system is actually trying to start a second
2662 <application>Privoxy</application> on the same port, which will not work.
2663 (You can have multiple instances but they must be assigned different ports.)
2664 How and why this might happen varies from platform to platform, but you need
2665 to check your installation and start-up procedures.
2669 <sect2 renderas="sect3" id="demoronizer">
2671 Pages with UTF-8 fonts are garbled.
2674 This may be the result of an overly aggressive filter. The filters that
2675 are enabled in the default configuration aren't expected to cause problems
2676 like this. If you enabled the <quote>demoronizer</quote> filter, please
2677 try temporarily disabling it.
2680 If that doesn't help, temporarily disable all filters to see if another
2681 filter could be the culprit. If the problem disappears, enable the filters
2682 one by one, until the problem reappears and the offending filter is found.
2685 Once the problem-causing filter is known, it can be fixed or disabled.
2688 Upgrading <application>Privoxy</application>, or going to the most recent
2689 <filename>default.action</filename> file available from <ulink
2690 url="https://sourceforge.net/project/showfiles.php?group_id=11118">SourceForge</ulink>
2691 might be worth a try, too.
2695 <sect2 renderas="sect3" id="demoronizer2">
2697 Why are binary files (such as images) corrupted when Privoxy
2701 This may also be caused by an (<link linkend="DEMORONIZER">overly aggressive
2702 filter</link> in conjunction with a web server that is misreporting the content
2703 type. By default binary files are exempted from
2704 <application>Privoxy's</application> filtering
2705 (unless the web server by mistake says the file is something else).
2709 <sect2 renderas="sect3" id="demoronizer3">
2711 What is the <quote>demoronizer</quote> and why is it there?
2714 The original demoronizer was a Perl script that cleaned up HTML pages which
2715 were created with certain Microsoft products. MS has used proprietary extensions
2716 to standardized font encodings (ISO 8859-1), which has caused problems for pages
2717 that are viewed with non-Microsoft products (and are expecting to see a
2718 standard set of fonts). The demoronizer corrected these errors so the pages
2719 displayed correctly. <application>Privoxy</application> borrowed from this
2720 script, introducing a filter based on the original demoronizer, which in turn could
2721 correct these errors on the fly.
2724 But this is only needed in some situations, and will cause serious problems in some
2728 If you are using Microsoft products, you do not need it. If you need to view
2729 pages with UTF-8 characters (such as Cyrillic or Chinese), then it will
2730 cause corruption of the fonts, and thus <emphasis>should not be on</emphasis>.
2733 On the other hand, if you use non-Microsoft products, and you occasionally
2734 notice weird characters on pages, you might want to try it.
2738 <sect2 renderas="sect3" id="windowopen">
2740 Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code?
2743 <application>Privoxy</application> is attempting to disable malicious
2744 <ulink url="http://en.wikipedia.org/wiki/Javascript">Javascript</ulink>
2745 in this case, with the <literal>unsolicited-popups</literal>
2746 filter. <application>Privoxy</application> cannot tell very well
2747 <quote>good</quote> code snippets from <quote>bad</quote> code snippets.
2750 If you see this in HTML source, and the page displays without problems, then
2751 this is good, and likely some pop-up window was disabled. If you see this
2752 where it is causing a problem, such as a downloaded program source code file,
2753 then you should set an exception for this site or page such that the
2754 integrity of the page stays in tact by disabling all filtering.
2758 <sect2 renderas="sect3" id="dnserrors">
2760 I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why
2761 can't Privoxy do this better?
2764 There are potentially several factors here. First of all, the DNS resolution
2765 is done by the underlying operating system -- not
2766 <application>Privoxy</application> itself. <application>Privoxy</application>
2767 merely initiates the process and hands it off, and then later reports
2768 whatever the outcome was and tries to give a coherent message if there seems
2769 to be a problem. In some cases, this might otherwise be mitigated by the
2770 browser itself which might try some work-arounds and alternate approaches (e.g
2771 adding <quote>www.</quote> to the URL).
2774 In other cases, if <application>Privoxy</application> is being chained
2775 with another proxy, this could complicate the issue, and cause undue
2776 delays and timeouts. In the case of a <quote>socks4a</quote> proxy, the socks
2777 server handles all the DNS. <application>Privoxy</application> would just be
2778 the <quote>messenger</quote> which is reporting whatever problem occurred
2779 downstream, and not the root cause of the error.
2783 In any case, versions newer than 3.0.3 include various improvements to help
2784 <application>Privoxy</application> better handle these cases.
2788 <sect2 renderas="sect3" id="allcpu">
2790 At one site Privoxy just hangs, and starts taking
2791 all CPU. Why is this?
2794 This is probably a manifestation of the <quote>100% cpu</quote> problem that
2795 occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines
2796 are in the raw HTML source of the page, and the browser just ignores them. But the
2797 pattern matching in <application>Privoxy's</application> page filtering
2798 mechanism is trying to match against absurdly long strings and this becomes
2799 very CPU-intensive, taking a long, long time to complete.
2802 Until a better solution comes along, disable filtering on these pages,
2803 particularly the <literal>js-annoyances</literal> and
2804 <literal>unsolicited-popups</literal> filters. If you run into this problem
2805 with a recent &my-app; version, please send a problem report.
2809 <sect2 renderas="sect3" id="slowcrawl">
2810 <title>I just installed Privoxy, and all my
2811 browsing has slowed to a crawl. What gives? </title>
2813 This should not happen, and for the overwhelming number of users world-wide,
2814 it does not happen. I would suspect some inadvertent interaction of software
2815 components such as anti-virus software, spyware protectors, personal
2816 firewalls or similar components. Try disabling (or uninstalling) these one
2817 at a time and see if that helps. Either way, if you are using a
2818 recent &my-app; version, please report the problem.
2822 <sect2 renderas="sect3" id="preventcomp">
2823 <title>Why do my filters work on some sites but not on others? </title>
2825 It's probably due to compression. It is a common practice for web servers to
2826 send their content <quote>compressed</quote> in order to speed things up, and
2827 then let the browser <quote>uncompress</quote> them. When compiled with zlib support
2828 &my-app; can decompress content before filtering, otherwise you may want to enable
2830 url="../user-manual/actions-file.html#PREVENT-COMPRESSION">prevent-compression</ulink>.
2833 As of &my-app; 3.0.9, zlib support is enabled in the default builds.
2838 <sect2 renderas="sect3" id="ssl-warnings">
2839 <title>On some HTTPS sites my browser warns me about unauthenticated content,
2840 the URL bar doesn't get highlighted and the lock symbol appears to be broken.
2841 What's going on?</title>
2843 Probably the browser is requesting ads through HTTPS and &my-app;
2844 is blocking the requests. Privoxy's error messages are delivered
2845 unencrypted and while it's obvious for the browser that the HTTPS
2846 request is already blocked by the proxy, some warn about unauthenticated
2850 To work around the problem you can redirect those requests to an invalid
2851 local address instead of blocking them. While the redirects aren't
2852 encrypted either, many browsers don't care. They simply follow the
2853 redirect, fail to reach a server and display an error message instead
2857 To do that, enable logging to figure out which requests get blocked by
2858 &my-app; and add the hosts (no path patterns) to a section like this:
2862 {+redirect{http://127.0.0.1:0/} -block -limit-connect}
2867 Additionally you have to configure your browser to contact
2868 <quote>127.0.0.1:0</quote> directly (instead of through &my-app;).
2871 To add a proxy exception in <application>Mozilla Firefox</application>
2872 open the <quote>Preferences</quote>, click the <quote>Settings</quote>
2873 button located on the <quote>Network</quote> tab in the <quote>Advanced</quote>
2874 section, and add <quote>127.0.0.1:0</quote> in the <quote>No Proxy for:</quote>
2880 <sect2 renderas="sect3" id="se-linux">
2881 <title>I get selinux error messages. How can I fix this?</title>
2883 Please report the problem to the creator of your selinux policies.
2886 The problem is that some selinux policy writers aren't familiar
2887 with the application they are trying to <quote>secure</quote> and
2888 thus create policies that make no sense.
2891 In <application>Privoxy's</application> case the problem usually
2892 is that the policy only allows outgoing connections for certain
2893 destination ports (e.g. 80 and 443). While this may cover the
2894 standard ports, websites occasionally use other ports as well.
2895 This isn't a security problem and therefore <application>Privoxy's</application>
2896 default configuration doesn't block these requests.
2899 If you really want to block these ports (and don't be able
2900 to load websites that don't use standard ports), you should
2901 configure Privoxy to block these ports as well, so it doesn't
2902 trigger the selinux warnings.
2907 <sect2 renderas="sect3" id="gentoo-ricers">
2908 <title>I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why?</title>
2910 Probably you unintentionally compiled &my-app; without threading support
2911 in which case requests have to be serialized and only one can be served
2915 Check your <quote>USE</quote> flags and make sure they include
2916 <quote>threads</quote>. If they don't, add the flag and rebuild &my-app;.
2919 If you compiled &my-app; with threading support (on POSIX-based systems),
2920 the <quote>Conditional #defines</quote> section on <ulink
2921 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2922 will list <quote>FEATURE_PTHREAD</quote> as <quote>enabled</quote>.
2926 <sect2 renderas="sect3" id="tainted-sockets">
2927 <title>What are tainted sockets and how do I prevent them?</title>
2929 &my-app; marks sockets as tainted when it can't use them to
2930 serve additional requests.
2931 This does not necessarily mean that something went wrong and
2932 information about tainted sockets is only logged if connection
2933 debugging is enabled (debug 2).
2936 For example server sockets that were used for CONNECT requests
2937 (which are used to tunnel https:// requests) are considered tainted
2938 once the client closed its connection to &my-app;.
2939 Technically &my-app; could keep the connection to the server open,
2940 but the server would not accept requests that do not belong to the
2941 previous TLS/SSL session (and the client may even have terminated
2945 Server sockets are also marked tainted when a client requests a
2946 resource, but closes the connection before &my-app; has completely
2947 received (and forwarded) the resource to the client.
2948 In this case the server would (probably) accept additional requests,
2949 but &my-app; could not get the response without completely reading
2950 the leftovers from the previous response.
2953 These are just two examples, there are currently a bit more than
2954 25 scenarios in which a socket is considered tainted.
2957 While sockets can also be marked tainted as a result of a technical
2958 problem that may be worth fixing, the problem will be explicitly
2963 <sect2 renderas="sect3" id="pcre-stack-limit">
2964 <title>After adding my custom filters, &my-app; crashes when visitting certain websites</title>
2966 This can happen if your custom filters require more memory than &my-app;
2968 Usually the problem is that the operating system enforces a stack size limit
2969 that isn't sufficient.
2972 Unless the problem occurs with the filters available in the default configuration,
2973 this is not considered a Privoxy bug.
2976 To prevent the crashes you can rewrite your filter to use less resources,
2977 increase the relevant memory limit or recompile pcre to use less stack space.
2978 For details please see the
2979 <ulink url="http://pcre.org/original/doc/html/pcrestack.html">pcrestack man page</ulink>
2980 and the documentation of your operating system.
2984 <sect2 renderas="sect3" id="file-permissions">
2985 <title>What to do if editing the config file of privoxy is access denied?</title>
2987 Your userid probably isn't allowed to edit the file.
2988 <!-- show how to check permissions? -->
2989 On Windows you can use the windows equivalent of sudo:
2991 <screen>runas /user:administrator "notepad \privoxy\config.txt"</screen>
2994 or fix the file permissions:
2996 <screen>C:\Privoxy>icacls config.txt
2997 config.txt BUILTIN\Administrators:(I)(F)
2998 NT AUTHORITY\SYSTEM:(I)(F)
2999 BUILTIN\Users:(I)(RX)
3000 NT AUTHORITY\Authenticated Users:(I)(M)
3002 Successfully processed 1 files; Failed processing 0 files
3004 C:\Privoxy>icacls config.txt /grant Lee:F
3005 processed file: config.txt
3006 Successfully processed 1 files; Failed processing 0 files
3008 C:\Privoxy>icacls config.txt
3009 config.txt I3668\Lee:(F)
3010 BUILTIN\Administrators:(I)(F)
3011 NT AUTHORITY\SYSTEM:(I)(F)
3012 BUILTIN\Users:(I)(RX)
3013 NT AUTHORITY\Authenticated Users:(I)(M)
3015 Successfully processed 1 files; Failed processing 0 files
3017 C:\Privoxy></screen>
3020 or try to point-n-click your way through adjusting the file
3021 permissions in windows explorer.
3027 <!-- ~~~~~ New section ~~~~~ -->
3028 <sect1 id="contact"><title>Contacting the developers, Bug Reporting and Feature Requests</title>
3029 <!-- Include contacting.sgml -->
3031 <!-- end contacting -->
3034 <!-- ~~~~~ New section ~~~~~ -->
3035 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
3037 <!-- Include copyright.sgml -->
3043 Portions of this document are <quote>borrowed</quote> from the original
3044 <application>Junkbuster</application> (tm) FAQ, and modified as
3045 appropriate for <application>Privoxy</application>.
3048 <!-- ~~~~~ New section ~~~~~ -->
3049 <sect2><title>License</title>
3050 <!-- Include copyright.sgml: -->
3052 <!-- end copyright -->
3054 <!-- ~ End section ~ -->
3056 <!-- ~~~~~ New section ~~~~~ -->
3057 <sect2><title>History</title>
3058 <!-- Include history.sgml -->
3064 <!-- ~ End section ~ -->
3067 <!-- ~~~~~ New section ~~~~~ -->
3069 <sect1 id="seealso"><title>See also</title>
3071 <!-- Include seealso.sgml -->
3081 This program is free software; you can redistribute it
3082 and/or modify it under the terms of the GNU General
3083 Public License as published by the Free Software
3084 Foundation; either version 2 of the License, or (at
3085 your option) any later version.
3087 This program is distributed in the hope that it will
3088 be useful, but WITHOUT ANY WARRANTY; without even the
3089 implied warranty of MERCHANTABILITY or FITNESS FOR A
3090 PARTICULAR PURPOSE. See the GNU General Public
3091 License for more details.
3093 The GNU General Public License should be included with
3094 this file. If not, you can view it at
3095 http://www.gnu.org/copyleft/gpl.html
3096 or write to the Free Software Foundation, Inc.,
3097 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA